only thing about it has to be 4 wires, but being it's that old it may be grandfathered in. more knowledgble people will be along shortly.

 

Thanks for the tips, everyone! This is a great start.

Only thing about it has to be 4 wires, but being it's that old it may be grandfathered in. more knowledgable people will be along shortly.

My understanding is a lot of the wiring in this house is grandfathered in. Some of it is original and ungrounded. Yikes!

You need ground.
You need neutral.
Since you only have 1 remaining wire, you'll need to wire the panel as 120V. Pigtail the hot wire to both main lugs on the panel.
There will be no way to get 240V out of this panel until you replace the feeder. Which might be something to think about, but you'd want a bigger panel if you ever do that.

This will work fine as long as the existing circuits don't include any MWBCs (shared neutral, 1 cable with 2 hots and 1 neutral). If you have any of those, simply put both hot wires in the same 120V breaker. QO breakers are listed for 2 wires per terminal as long as they're copper.

In this situation, what would be the bet way to add a ground rod? The carport (concrete slab) is on the other side of this wall.

Do I not have neutral? I might need someone to explain this one to me. The current feeder line is black, white, bare.

I'll think about replacing the feeder but it might be a separate project for another day.

Your also going to have to install a breaker to feed the panel. I do not see power lugs.

If you need 240v you going to need a new cable from the service with 2 hots a neutral and a ground, 4 wires.

All neutrals and grounds are separated after the service in all situations. If it was right before it is wrong now.

There is a breaker in the house's breaker box that feeds the garage. Initially, I planned on using that as the main breaker for the garage subpanel. Then I learned about backfeeding and considered that for a bit. Considering that the existing feeder line isn't long enough to reach the new panel, I'll likely install a main breaker in a separate box which then continues on to provide power to the garage panel.

As Jim pointed out, the lugs are under the keyhole slots.

The lugs are at the top of the bus on the outside corners. One is under the keyhole slot on the right.

You should have a means of disconnect to kill power as I t enters the workshop.

RE: Main disconnect, see comment above.

 

You need ground.
You need neutral.
Since you only have 1 remaining wire, you'll need to wire the panel as 120V. Pigtail the hot wire to both main lugs on the panel.
There will be no way to get 240V out of this panel until you replace the feeder. Which might be something to think about, but you'd want a bigger panel if you ever do that.

This will work fine as long as the existing circuits don't include any MWBCs (shared neutral, 1 cable with 2 hots and 1 neutral). If you have any of those, simply put both hot wires in the same 120V breaker. QO breakers are listed for 2 wires per terminal as long as they're copper.

 

Your also going to have to install a breaker to feed the panel. I do not see power lugs.

If you need 240v you going to need a new cable from the service with 2 hots a neutral and a ground, 4 wires.

All neutrals and grounds are separated after the service in all situations. If it was right before it is wrong now.

 

Your also going to have to install a breaker to feed the panel. I do not see power lugs.

A breaker to feed the panel (like a main breaker for the subpanel) would only be required if a) the garage is a stand-alone building (detached). But even if it is, in such a small panel OP can simply rely on the "Rule of Six" which says a mandatory disconnect can be up to 6 breaker throws (hand movements).

Although, now that you mention it, you can easily get a main disconnet on any 120V panel. Use a jumper wire to connect the two supply lugs to each other which effectively turns it into a 120V "no lugs" panel. Then, backfeed the panel using a regular breaker and label that "main disconnect".

In this situation, what would be the bet way to add a ground rod? The carport (concrete slab) is on the other side of this wall.
Do I not have neutral? I might need someone to explain this one to me. The current feeder line is black, white, bare.

The ground rod is not necessary unless the building is detached. It's needed if it's detached, to deal with lightning and ESD and other "naturally sourced" electricity. However, a ground rod is NOT a substitute for a ground wire - the dirt can't carry enough current to deal with "human sourced" electricity faults. All it'll do is energize the dirt.

Anyway your cable is black-white-bare. You need neutral since you need to support 120V loads, and the only wire that can possibly be neutral is the white wire. Thus the bare wire is useless for anything but a ground wire, and you might as well use it for that.

There is a breaker in the house's breaker box that feeds the garage. Initially, I planned on using that as the main breaker for the garage subpanel. Then I learned about backfeeding and considered that for a bit. Considering that the existing feeder line isn't long enough to reach the new panel, I'll likely install a main breaker in a separate box which then continues on to provide power to the garage panel.

Well as I said up top, your 6-space panel won't need a main disconnect, because it has 6 or fewer breaker throws. If you stuffed it with tandems you might have a problem, but then you can use the backfeeding trick I mentioned above.

I'm not concerned about the lack of 240 capability. I've never needed it before and figure if I need it in the future then I'll worry about it then.

Exactly. Getting 240V on your existing wires would be a nightmare. It would require a transformer. Even if you need EV charging out there, you can get "double level 1" charging by running 120V at 30A. Giving 75-110 miles in 10 hours of charging. And you can do that with an Emporia wall unit linked to an Emporia home energy monitor in the subpanel (it watches your energy use and reduces EV charge rate by whatever amps you're using for other things - start up your circular saw and the car backs off from 2.8kw to 1.1kW. Through the magic of 1980s era microcontroller technology LOL.)

 

The lugs are at the top of the bus on the outside corners. One is under the keyhole slot on the right.

You should have a means of disconnect to kill power as I t enters the workshop.

 

Don't worry about a ground rod, you hardly have anything to code anyway. The ground rod would add nothing.
You do have a neutral, it would be the white wire. If that is what is connected in the main panel to the neutral bus.
As mentioned, you can't have 240V, you would have to either add a jumper for the lugs in the subpanel or "pigtail" the hot into two and connect to each lug.
If you don't add the jumper or pigtail, only every other breaker will work.
It's fine to add a junction box to extend the wire. In fact, I would just put a box in and a single pole switch, then up to your panel. That way you have a disconnect for the panel.

 

I'm not concerned about the lack of 240 capability. I've never needed it before and figure if I need it in the future then I'll worry about it then.

I believe I'll add a junction box to extend the wiring to the panel and then install a switch box next to the panel. That way everything is in the same spot.

 

The big cable running across the photo below the breaker box is a line that goes from the house to a 3-way switch in the garage (the other switch is in the kitchen) that turns the carport lights on and off. Current plan is to leave this circuit as it is because this circuit doesn't involve the garage wiring and I don't feel like messing with it.

You don't want to leave that circuit as it is. It is subject to physical damage. That wasn't code compliant in 1940 so it is not grandfathered now. The minimum that should be done with that cable is to move it up to the Inside edge of the top plate of the wall so that it will not end up with hand cultivators or anything else hanging off it nor leaning on it. The insulation of the conductors in that cable is very likely to be natural rubber. Rubber continues to harden from the day it is made until it turns into small granules which have no insulating properties at all. That physical condition is very conducive to arcing faults which can kindle a fire. The reason that I suggest running it on the front of the wall's top plate is because code forbids it being run either directly above nor below your new panel. The space directly above and below a panel is reserved for cables and raceways which are connected to that panel. The front of the wall's top panel will not be in that space. Please keep in mind that every time that old cable is manipulated or struck by a tool the insulation is likely to get damaged. When the rubber insulation is as old as what is in that cable is likely to be allowing anything to come in contact with it is likely to damage that insulation. That is why it really does need to be protected or replaced.

If you can bring yourself to do it change that circuit to modern cable right were it comes out of the ground using a weather proof box on the outside of the building. Use a deep double gang box so that you will not have to manipulate the cable more than absolutely necessary. Pushing those old wires back into a single gang box is almost certain to damage them. Have the new non metallic cable, type NM, enter the box through the threaded opening on the back of that box so that no portion of the NM cable is exposed to the weather. NM is never suitable for use outdoors even if it were run in conduit.

Can I simply connect the 10/2 that was going to the old fuse box to the new breaker box as long as I don't exceed 30 amps?

Yes you can. Just remember that doesn't mean that the sum of all the breakers is the way to figure how much ampacity that you need. For shop purposes you should, strictly as a practical matter and not for code compliance, check all of the labels of your equipment and figure out what is the largest total current you need to run the tool/s that you would actually use at one time, then add 25% of the largest of those tools Full Load Amperes (FLA) from it's name plate. There is a code compliant way to calculate the load but in your case the actual load will be the larger value and therefore the amperage that you will need to run the loads that you will run at the same time. Second thing to point out is that the Building Disconnecting Means; in the form of the 30 ampere, double pole breaker will not provide protection from overloading the feeder conductors. Since each pole of the breaker can carry 30 amperes of current, together they would allow an overload of the feeder conductors up to 6o amperes. The overload protection for the feeder is the single pole 30 ampere breaker in the house panel.

Since the existing main power wire isn't long enough, can I install a junction box near the floor (on those 2x4s where the old fuse box use to be mounted) and then install new wiring from there?

Yes you can. Feeders can always be spliced with the exception of some very special types. I hope that you will not be too disappointed to find that your feeder is not special in one of those ways.

Don't worry about a ground rod, you hardly have anything to code anyway. The ground rod would add nothing.

I have to disagree with this. The code gives the reasons for grounding the electrical system as: stabilize the system voltage to earth during normal operating conditions and to limit excess voltages on the system due to lightning, line surges, and accidental contact with higher voltage lines. Your detached garage, and everything that is connected to the wiring within it, is susceptible to all three of the hazards listed in the second sentence. The code requires that the Building Disconnecting Means be arranged to keep the Equipment Grounding Conductor isolated from the Grounded Current Carrying Conductor (GCCC). In this case the GCCC is not a "Neutral." At a building supplied by a feeder only the Equipment Grounding Conductor is bonded to the equipment enclosure and connected to the Grounding Electrode Conductor. All of those terminations will be done on an accessory EGC busbar that screws directly to the panel's enclosing cabinet through the holes that have been drilled and tapped for that purpose by the manufacturer. The Grounding Electrode Conductor is connected to a minimum of 2 driven rod electrodes spaced not less than 6 feet apart. You do not have to run the GEC out the wall were the feeder conductors enter. You can run it out at the nearest point were the rods can be readily driven. There is no required depth of bury for grounding electrode conductors nor for driven rod electrodes. But if you are using 8 foot long rods you must bury them in order to have at least 8 feet of rod in contact with the soil as the code requires. Prudence would suggest that the EGC and the tops of the rods be at least 1 foot underground to prevent contact with power landscaping equipment or casual digging for any purpose. I would suggest that you run a plastic tape printed with the words buried electrical cable below ~6 inches above it so that the tape will be encountered prior to the rods or the GEC being damaged if someone is digging near them.

There is a technique that you could apply that would add a lot of current surge and voltage spike resistance to your wiring but the tone of your previous postings suggests that you are not interested in doing additional work over what the code requires. If I'm wrong about that please let me know and I will describe the technique for your consideration.

It's fine to add a junction box to extend the wire. In fact, I would just put a box in and a single pole switch, then up to your panel. That way you have a disconnect for the panel.

A snap switch is not labeled as "Suitable For Use As Service Equipment" which the code requires the Building Disconnecting Means to be. A properly installed breaker or switch in the panel enclosure would meet that requirement as long as the panel's label has that wording on it. Using the back fed but anchored in place circuit breaker is the least expensive device for meeting the requirement and the least work to install.

Tom Horne

 

You don't want to leave that circuit as it is. It is subject to physical damage. That wasn't code compliant in 1940 so it is not grandfathered now. The minimum that should be done with that cable is to move it up to the Inside edge of the top plate of the wall so that it will not end up with hand cultivators or anything else hanging off it nor leaning on it. The insulation of the conductors in that cable is very likely to be natural rubber. Rubber continues to harden from the day it is made until it turns into small granules which have no insulating properties at all. That physical condition is very conducive to arcing faults which can kindle a fire. The reason that I suggest running it on the front of the wall's top plate is because code forbids it being run either directly above nor below your new panel. The space directly above and below a panel is reserved for cables and raceways which are connected to that panel. The front of the wall's top panel will not be in that space. Please keep in mind that every time that old cable is manipulated or struck by a tool the insulation is likely to get damaged. When the rubber insulation is as old as what is in that cable is likely to be allowing anything to come in contact with it is likely to damage that insulation. That is why it really does need to be protected or replaced.

If you can bring yourself to do it change that circuit to modern cable right were it comes out of the ground using a weather proof box on the outside of the building. Use a deep double gang box so that you will not have to manipulate the cable more than absolutely necessary. Pushing those old wires back into a single gang box is almost certain to damage them. Have the new non metallic cable, type NM, enter the box through the threaded opening on the back of that box so that no portion of the NM cable is exposed to the weather. NM is never suitable for use outdoors even if it were run in conduit.

Yes you can. Just remember that doesn't mean that the sum of all the breakers is the way to figure how much ampacity that you need. For shop purposes you should, strictly as a practical matter and not for code compliance, check all of the labels of your equipment and figure out what is the largest total current you need to run the tool/s that you would actually use at one time, then add 25% of the largest of those tools Full Load Amperes (FLA) from it's name plate. There is a code compliant way to calculate the load but in your case the actual load will be the larger value and therefore the amperage that you will need to run the loads that you will run at the same time. Second thing to point out is that the Building Disconnecting Means; in the form of the 30 ampere, double pole breaker will not provide protection from overloading the feeder conductors. Since each pole of the breaker can carry 30 amperes of current, together they would allow an overload of the feeder conductors up to 6o amperes. The overload protection for the feeder is the single pole 30 ampere breaker in the house panel.

Yes you can. Feeders can always be spliced with the exception of some very special types. I hope that you will not be too disappointed to find that your feeder is not special in one of those ways.

I have to disagree with this. The code gives the reasons for grounding the electrical system as: stabilize the system voltage to earth during normal operating conditions and to limit excess voltages on the system due to lightning, line surges, and accidental contact with higher voltage lines. Your detached garage, and everything that is connected to the wiring within it, is susceptible to all three of the hazards listed in the second sentence. The code requires that the Building Disconnecting Means be arranged to keep the Equipment Grounding Conductor isolated from the Grounded Current Carrying Conductor (GCCC). In this case the GCCC is not a "Neutral." At a building supplied by a feeder only the Equipment Grounding Conductor is bonded to the equipment enclosure and connected to the Grounding Electrode Conductor. All of those terminations will be done on an accessory EGC busbar that screws directly to the panel's enclosing cabinet through the holes that have been drilled and tapped for that purpose by the manufacturer. The Grounding Electrode Conductor is connected to a minimum of 2 driven rod electrodes spaced not less than 6 feet apart. You do not have to run the GEC out the wall were the feeder conductors enter. You can run it out at the nearest point were the rods can be readily driven. There is no required depth of bury for grounding electrode conductors nor for driven rod electrodes. But if you are using 8 foot long rods you must bury them in order to have at least 8 feet of rod in contact with the soil as the code requires. Prudence would suggest that the EGC and the tops of the rods be at least 1 foot underground to prevent contact with power landscaping equipment or casual digging for any purpose. I would suggest that you run a plastic tape printed with the words buried electrical cable below ~6 inches above it so that the tape will be encountered prior to the rods or the GEC being damaged if someone is digging near them.

There is a technique that you could apply that would add a lot of current surge and voltage spike resistance to your wiring but the tone of your previous postings suggests that you are not interested in doing additional work over what the code requires. If I'm wrong about that please let me know and I will describe the technique for your consideration.

A snap switch is not labeled as "Suitable For Use As Service Equipment" which the code requires the Building Disconnecting Means to be. A properly installed breaker or switch in the panel enclosure would meet that requirement as long as the panel's label has that wording on it. Using the back fed but anchored in place circuit breaker is the least expensive device for meeting the requirement and the least work to install.

Tom Horne

Wow, thank you for all of this info! A lot to digest here.

Just for the record, my main reason for not wanting to do TOO much here is that - ideally - we hope to sell the house in a few years and would prefer to save up for the next house rather than invest a whole lot more into this one. I'm really just trying to update the garage a little without going all in.

Below is a photo showing where the wiring for the carport light enters (the old, possibly rubber wiring). Interestingly, a more modern wire was used to run it underground from the house (where one of the light switches is) to the garage (where the other switch is). I'm not sure why they decided to use old wire other than perhaps it was pulled from somewhere and reused. And I cannot say whether the underground wiring is enclosed in conduit or not.

NOTE: This entry point and junction box is at the entrance to the garage just inside the door frame (to the left). The breaker box and feeder line are along this same wall a few feet from here.

Here is a photo of the switch for the carport light. There is also a flood light attached to this switch that lights up the driveway but I intend on removing the flood light from this circuit, replacing it with a Ring camera flood light, and putting it on the new garage breaker box because it needs constant power and not switched power.

Lastly, just to satisfy any curiosity, the feeder wire from the house to the garage is Columbia "sunlight resistant" 10/2 with ground. As with the carport wiring, I do not know if this wiring is in conduit under the driveway or not.

The Shop Vac appears to draw the most current at around 11.5 amps. Next would be my drill press which has a 5-amp motor. Sometimes I run them both at the same time with the vacuum acting as a dust collector.

Regarding the ground, can the ground wire travel through the wall in the same manner as the switch/receptacle wiring? If so, I could drive an 8-foot rod at the back of the garage.

I'm curious about this technique you mention. Feel free to inform me about it.

And it sounds like backfeeding or adding a box for a single breaker acting as a disconnect will be the route I take here. Leaning toward backfeeding since I will have the breaker slots to spare.

 

I snapped a few more photos this morning of what I'm working with. See below.

Even though I have 4 breakers in right now, I really only plan on using 3. It's a small garage (10x18). I highly doubt I'll ever need all 6 breaker slots.

If a ground rod is indeed necessary, what's the proper way to add it when there is a concrete slab on all sides of the panel? Nearest bit of bare earth is perhaps 4-6 feet at the entrance to the garage.

Lastly, if anyone is wondering, no, I don't plan on insulating the walls. I just wanted to get sheathing up for a cleaner look and to help seal out bugs. My understanding was that adding insulation would require a vapor barrier and in my climate (hot and humid) I would have to add that between the studs and the siding (those horizontal slats). That's too much work and expense.

 

Might want to cut off some of that yellow goop and give it a flame test, outdoors. Just don't breathe the fumes! A lot of that stuff is north of napalm on the "flammability" chart and the fumes will incapacitate you.

On those wires, I would just put a 4-11/16" steel junction box there and extend the wires using some 10/2 w/g Romex and wire nuts. Better hardware stores or lumber supply (i.e. not big-box chains) will cheerfully sell you wire by the foot, usually cheaper than a "short spool" at the big-box.

if a ground rod is indeed necessary, what's the proper way to add it when there is a concrete slab on all sides of the panel? Nearest bit of bare earth is perhaps 4-6 feet at the entrance to the garage.

You don't need a ground rod if the garage is physically attached to the house. The minimum qualification for "attached" is a connecting breezeway or shared wall, interior passage not required.

If you do, the ground rod isn't required to be underneath or near the panel. In a perfect word the guy who poured the slab left you a bit of re-rod sticking out for use as an Ufer ground, but otherwise go put rods where able. 2 rods at least 6' apart, farther lets it do its job better. You can do 1 rod if it passes an impedance test, but the test is more costly than a second ground rod LOL.

 

A green screw is not required to ground the box. A lug could be used with any screw with xx-32 threads into the box or a bolt and nut can be used to attach a lug. The paint should be scraped under the lug. A plastic box will not corrode outside.

 

I thought of something just now while I was outside walking our dog -- part of the feeder wire is visible outside the garage. That's a bit of weathered canned foam poking out. The concrete you see is the carport slab. It's covered by a roof. Why this is the way it is, with a portion of the siding cut out, is beyond me.

 

You might want to cover the cable and the gap in the siding with a 4&11/16 square cover which looks like this

and not like this

The open edged slots are too easy to dislodge from the fasteners.
Paint it well on both sides to prevent rusting. Ask in a paint store; rather than a Big Box Store; for a paint to cover galvanized metal. I would GUESS that might be some version of Rust-Oleum spray paint. Paint both sides of the plate before installing it. That will provide physical protection to the exposed cable including from critters in search of nesting materials who may chew on the jacket unless it is the hard plastic type.

If you are willing to do so please provide a photograph of the carport roof's underside and framing. I have an idea that you might like.

Tom Horne

 

That opening is an access requirement according to the Mouse Building Code. Most people don't bother reading that code because it is, after all, written in mouse language

Seriously, I did find it odd that your wires were individual wires and that there was not a cable sheath or conduit around them. If you can find where that sheath begins I would find a way to slide some conduit down the wires so it overlaps the sheath. The wires really need protection of either a sheath or conduit. Code doesn't let you have wires outside of the sheath unless it's in a junction box, but I have a feeling cable replacement cost would be prohibitive.

 

That opening is an access requirement according to the Mouse Building Code. Most people don't bother reading that code because it is, after all, written in mouse language

Seriously, I did find it odd that your wires were individual wires and that there was not a cable sheath or conduit around them. If you can find where that sheath begins I would find a way to slide some conduit down the wires so it overlaps the sheath. The wires really need protection of either a sheath or conduit. Code doesn't let you have wires outside of the sheath unless it's in a junction box, but I have a feeling cable replacement cost would be prohibitive.

I can get 100 feet of #2 aluminum 2/2/2/4 for $250. I've considered it but I'm really trying not to make this a project bigger than it is.

Those individual wires actually appear to have originally been insulated together, along with the ground wire, to form a cable that looks similar to Romex. Like, imagine Romex if it were a solid insulated cable rather than sheathed.

 

I took a few minutes this morning to investigate where the feeder is coming from the ground and entering the garage. It does not appear to be buried in any conduit but I can't verify that without digging up part of the driveway. Judging by the way the feeder is between the concrete slab and the cinder block foundation of the garage, my best guess is that the carport and its concrete slab were added on after the wiring was installed to the garage and that they simply ran the feeder up foundation of the garage and entered through the siding. I could be wrong.

I probed the gap between the carport and garage and took the photo below.

Anyway, I'll see about adding some conduit to protect the exposed portion of the feeder. I'd really like to get the wiring finished so I have power in there again. Once that's completed, I'll revisit the idea of replacing the feeder and the old rubber wiring for the carport lights.

 

Sounds like I'll be using the URD stuff then. 👍 Thanks for the info about SER.

It's my understanding you can not use URD after the meter. URD is not rated for indoor use. You'll need to use MHF 2-2-2-6 in conduit inside. in conduit or direct burial outside.

People also think they can put 100A on #2AL, You can't, it's only rated for 90.

 

I'll check in just a bit when I take my lunch hour.

 

The jacket didn't specify if that "12-3" meant 12-2 plus ground or 12-3 plus ground. Since it's a newer cable, I would think it's "plus ground" but there's no way of knowing for sure without pulling out one of these 3-way switches.

I do have a GFCI outlet in place. No worries there. After the breaker for that circuit, it's the first outlet on a chain of 3 outlets. The lighting will be on a different circuit. And then the flood light will be on a third breaker. I may install a fourth breaker for an exterior outlet in the carport but we'll cross THAT bridge when we get there.

Also, I'm giving more and more consideration to running a new feeder to the garage for full 100 amp service. If I go that route, do I need 2-2-4 or 2-2-2-4 aluminum wire? EDIT: Nevermind. I read that 2 hots are required for a subpanel. So 2-2-2-4 it is.

 

I'll let the pros/Code guys comment, but, personally, I would run individual conductors in conduit rather than do direct wire. You have to dig a trench either way.

 

I'll let the pros/code guys comment, but, personally, I would run individual conductors in conduit rather than do direct wire. You have to dig a trench either way.

Oh absolutely. If I'm going to redo the feeder then I'd like to do a little more than is required. I'm also using this as a learning experience. My wife and I have been wanting to turn a shipping container into a small home for a while now. I'll need to know all this stuff when we get to that point.

Conduit is not needed for SER. SER cannot be buried.

Sounds like I'll be using the URD stuff then. 👍 Thanks for the info about SER.

 

Conduit is not needed for SER. SER cannot be buried.

 

Since my last post, I shifted focus from rewiring to getting the sheathing up so I can finish the workbench and get my tools off the floor and have more space to work.

With that completed, I suppose it's time to shift back to electrical. I'm thinking of taking the plunge and ordering 80 feet of cable (should be enough). The question now is how on earth to run it from the main box and out the basement.

Here's a photo of the main box in all it's admittedly messy glory. Honestly, I can't wait to get out of this house but for now I'm stuck with it and have to work with what I've got.

Maybe it's because I'm not an electrician for a living but I'm thinking PVC conduit out the bottom, run it to the right so it rests atop the unfinished basement walls (there's basically a ledge of earth along the perimeter of the basement) and along the block wall foundation, then exit below the foundation and onward to the garage.

 

Since my last post, I shifted focus from rewiring to getting the sheathing up so I can finish the workbench and get my tools off the floor and have more space to work.

With that completed, I suppose it's time to shift back to electrical. I'm thinking of taking the plunge and ordering 80 feet of cable (should be enough). The question now is how on earth to run it from the main box and out the basement.

Here's a photo of the main box in all it's admittedly messy glory. Honestly, I can't wait to get out of this house but for now I'm stuck with it and have to work with what I've got.

Maybe it's because I'm not an electrician for a living but I'm thinking PVC conduit out the bottom, run it to the right so it rests atop the unfinished basement walls (there's basically a ledge of earth along the perimeter of the basement) and along the block wall foundation, then exit below the foundation and onward to the garage.

View attachment 740894

Somewhere along this thread I got it into my head that you have a Meter Mains assembly that includes both the meter socked and a main breaker which serves as the Service Disconnecting Means. While going over the postings again I realized that I cannot now find any solid indication of that. Is there a main breaker, switch, or fused pullout in the same enclosure as the meter socket? Like these

It would have a separate compartment for the main breaker as these 2 do.

This only going to be a partial list of the things you will need to address to make this main panel minimally safe, although nowhere near code compliant. First you will need to answer a couple of questions.

• Am I correct in concluding that this is a dug out basement with the lower walls and floor of earth?
• Is that panel hanging from the joist?
• Are you willing to put in the work to construct a proper support for it?
  • For someone inexperienced at dealing with the materials that I would suggest you would be looking at a full day of or work to do that.
• Will the panel's height fit between the joists and the ledge?
• How long is that Service Entry Cable, in wire feet, from were is comes out of the wall to were it enters the panel's enclosure?

I would strongly suggest that you address the most serious problems with this panel BEFORE you try to run the feeder to the garage because if you install the garage feeder prior to doing the most basic corrections to this Service Equipment you will be making the situation worse and when you go to sell the house it's present condition would be a huge RED Flag to the buyer's home inspector. The buyer will justifiably demand that the service be rebuilt from scratch. All of the necessary work is doable by you with a little bit of patience and some careful work. It won't even be physically hard to do.

Tom Horne

 

OK, that's super strange. That looks like a Ranch Panel, but it's not.

It looks like the main breaker is actally back-feeding - the supply side is the bus side. That would mean the bus stabs below that take regular breakers, may be completely unfused/unswitched and always-live.

Turn the main breaker off and see if those buses are still hot. I bet they are.

That would be a big deal if so, vis-a-vis your project. (be great for solar, though, you could support up to 160A of solar out of this!)

 

OK, that's super strange. That looks like a Ranch Panel, but it's not.

It looks like the main breaker is actally back-feeding - the supply side is the bus side. That would mean the bus stabs below that take regular breakers, may be completely unfused/unswitched and always-live.

Turn the main breaker off and see if those buses are still hot. I bet they are.

That would be a big deal if so, vis-a-vis your project. (be great for solar, though, you could support up to 160A of solar out of this!)

That's was my understanding as well when I opened up the cover. It looked to me like the power lines come in from the top of the meter, probably connect to the buses and are always hot, and then the breaker connects/disconnects power to the breaker box in the basement.

In that case, I imagine I could throw a 70 amp breaker in the meter box and send power on to the garage subpanel.

 

The sticker on the outside says "All circuit breakers are service disconnects"
That makes me think they intended for any circuits run out to be a feeder to a subpanel because the bond is in the meter/main. OP could still come out of there but would have to feed a small panel and run a 4-wire feeder. Of course that would depend on the load in the main panel. I say this because the breaker (OCPD) for a branch circuit is not called a "service disconnect".

 

OP could still come out of there but would have to feed a small panel and run a 4-wire feeder.

I'm not following your reasoning here. A feeder is a set of conductors between one Over Current Protective Device (OCPD), such as a circuit breaker, and the supply terminals of equipment holding other OCPDs. The code defines it thusly.

"Feeder. All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device."
(Emphasis mine)

Thus all of the breakers in that Service Equipment Enclosure are supplying Feeders unless they supply a single 240 volt load with no OCPD in between the load and the breaker in the service equipment.

Why do you say he would have to feed a small panel? A 4 wire feeder can be run from a 2 pole breaker and the neutral busbar in the Service Equipment to the panel in the detached garage. No other equipment is required between the two enclosures.

Tom Horne

 

@hornetd the one populated breaker is 200A.

Rule of Six was not outlawed until 2020 but a key idea associated with Rule of Six is oversubscribing a Rule of Six panel so the sum of breakers > the service size, with the Load Calculation being the only thing preventing overload. I believe that has been outlawed for some time.

 

I need to have chapter and verse on that if you have it to hand. My Church is preparing to relocate one of its youth summer camps. Such a Rule Of Six limitation could turn out to be a critical detail of the new electrical system. My experience with rule of six installations is fairly diverse and I have never failed inspection on one even though the total of the Overcurrent Protective Device ampacities was half again or more than the calculated load. The only limitation on the Rule Of Six that I was aware of thus far is it's use in panels that are used as service equipment to have up to 6 breakers as the Service Disconnecting Means. That was prohibited a requirement that all panels must be supplied by no more than 2 Over Current Protective Devices (OCPD) was added in 408.36.

408.36 Overcurrent Protection.
In addition to the requirement of 408.30, a panelboard shall be protected by an overcurrent protective device having a rating not greater than that of the panelboard. This overcurrent protective device shall be located within or at any point on the supply side of the panelboard.
Exception No. 2: Individual protection shall not be required for a panelboard protected on its supply side by two main circuit breakers or two sets of fuses having a combined rating not greater than that of the panelboard.
A panelboard constructed or wired under this exception shall not contain more than 42 overcurrent devices. For the purposes of determining the maximum of 42 overcurrent devices, a 2-pole or a 3-pole circuit breaker shall be considered as two or three overcurrent devices, respectively.

That would have prevented my installation of a 400 ampere Service with a Rule of Six MLO Service Equipment Panel ~2 decades ago at one of the youth Summer camps my church operates. I couldn't install that with an MLO panel now because the code now requires that a single panel be protected by not more than 2 OCPDs. The newer requirement that enclosures containing equipment which requires maintenance and testing while energized must have a single disconnecting means or be divided into separate compartments containing each OCPDs load terminals so that personnel will not have to work in an enclosure containing exposed energized parts would also prevent such an installation. As far as I know no such MLO panel with separate load compartments is available as yet. The requirement that panels

[Panning Tip; never let the builder install the underground conduit for any installation. They will make you unhappy with how they install the conduit and most especially how they arrange multiple conduits meant to be connected to a single enclosure. That in spite of having been provided with a knock out diagram, 1/2 inch thick plywood conduit termination template which was cut out to match the knockout pattern of the Service Equipment enclosure.]

The Service Equipment MLO panel which I installed then has the following breakers installed. 1)Dining hall 200 amperes, 2) 100 amperes staff cabin feeder supplying a 100 ampere panel with ~30 amperes 240 to each of 5 cabins. 30 amperes is definitely over the load calculation for those 2 twin bed sized cabins. 3) Water well and associated water purification equipment @ 30 amperes (In retrospect I should have gotten the electrical utility to install double terminal lugs on the load end of the meter socket and run separate service conductors to the well house to avoid the well pump being shut off during an emergency shut down of the utility which the staff does as soon as an alarm of fire is raised. That would assure a continuing supply of pressurized water for first aid firefighting. The code specifically allows the Service Disconnecting Means for such a well pump to be located separately from the other service disconnecting means for that reason), 4) office building @ 40 amperes, Bathhouse, shower trailers pedestal receptacle outlets @ 50 amperes 120/240 volts each (actual load being far less), 5) and art pavilion feeder @ 150 amperes. Because the water heating and cooking is done entirely with Liquefied Petroleum Gas (LPG) the calculation still comes out under 400 Amperes with a substantial reserve. The art pavilion pottery kiln is 60 amperes intermittent load when operating. It cycles on and off once it reaches it's operating temperature so that saved me from having to install a 75 ampere branch circuit for it because it is not a continuous load. It's contribution to the load calculation is therefore 60 amperes.

Is there some code language that you are aware of that would forbid the total ampacity of separately enclosed OCPDs from exceeding the Service Conductor ampacity? For example would six enclosed disconnects or breakers supplied by 400 ampere service conductors have to total to no more than 400 amperes. I have very seldom seen a multi disconnect service were the ampacity of the individual OCPDs didn't add up to more than the Service Conductor ampacity so if there is such a rule it is being observed mostly in the breach.

Tom Horne

 

I'm back! Can't believe it's been over a year and a half since I first started this project. Other projects pushed this to the back burner in that time but I think I'm ready to get back on it.

So after re-reading this thread, I believe this is the game plan:

• Install a 75 (?) amp breaker in the house's meter.
• Run the 2-2-2-4 aluminum URD that I already have down from the meter through 1.5" PVC conduit in an 18" trench. Threaded coupling out the bottom of the meter. 90 degree bend underground. Down the conduit. Another 90 bend at the garage up into an exterior junction box (?) where I transition from URD to whatever code states I can use indoors.
• Exterior junction box (?) transitions to indoor cable/wiring through the walls of the garage to the garage sub panel.
• Garage sub panel currently has 4 breakers: three 20A for the various electrical outlets plus one 15A breaker for the garage lighting. Totals 75 amps.
• I'm thinking of using the existing/previous 12/2 + ground service wiring that went under the driveway from the house to power a couple of outdoor outlets in the carport. Or maybe use it for a flood light illuminating the back yard or something. I figure the wiring is already there so why not use it somehow.

Thoughts? Thanks in advance!

 

Adding up the breaker handles is not how a feeder load is determined. A demand load calculation is the correct method.

A 75 amp breaker is not a standard size.

 

Ah, I overlooked the part about demand load calculation. To a non electrician, it sounds like gibberish. 😂

 

It may sound weird but it will save you money. The larger the system the more money it will save you. Some of the factors that go into the calculation are that 3 volt/amperes per square foot of occupiable floor area has been shown to be enough to provide the power for the lighting and, so called, convenience receptacle outlets in residential structures including their outbuildings. There are factors for heating and cooling loads, cooking loads, clothes washing and drying, and the list goes on. Each of those factors yields the amperage that is actually necessary to carry them. That is how the Service or Building disconnect is sized and also the size of the service entry conductors that bring the utility power to your Service Equipment. If you added up the circuit breaker ampacities to select the supply conductors and Disconnects you would overspend as much as half again what is actually needed for the loads you need to supply.

Tom Horne

 

Forget about 3/4 of what you read in this thread. It's an exercise in mental masturbation. Technically urd isn't right, not sure how much sleep I would lose over it to the garage. Number 2 fits in a 60 breaker and it's way cheap and on the shelf. This is ideal to run it from the outdoor panel. Run a wire to a ground rod, 8 or better.
That panel is ideal and made for this, 6 spaces plenty for this, save 2 for a charger or other loads. Using 2 would supply all your current load, can use more for convenience. 1 1/2 pipe is for 2 alum.

 

Forget about 3/4 of what you read in this thread. It's an exercise in mental masturbation. Technically URD isn't right, not sure how much sleep I would lose over it to the garage. Number 2 fits in a 60 breaker and it's way cheap and on the shelf. This is ideal to run it from the outdoor panel. Run a wire to a ground rod, 8 or better.
That panel is ideal and made for this, 6 spaces plenty for this, save 2 for a charger or other loads. Using 2 would supply all your current load, can use more for convenience. 1 1/2 pipe is for 2 alum.

Yeah, I realized only after purchasing 80 feet of 2224 URD that 1) it was the wrong cable for the job and 2) it's about twice as much length than I actually need. Something about the wire insulation not being rated for fire resistance.

EDIT: I'm just gonna get four 50 ft lengths of aluminum XHHW-2, each a different color (red, white, black, green), and run that through PVC conduit. That way I can use it underground and also within the walls.

 

Get the green a size smaller. a 4 will actually fit if you "clean" the hole in an aux bar just a bit. Saves wonky adapters. The estimation of real load is forever wayyyyyy off,, everyone thinks they are Edison and some of the retired electricians going thru their second childhood,,, I mean apprenticeship I guess are as bad as the amateurs. Right now you have 30A and could be wired the same as a travel trailer, I know a lot of people made it just fine with single circuit to a garage.
When I was 20 woud have thought differently,,, and did to the point of having 1000's of dollars of wire and pipe "parked" in the ground just in case decades later.
Having said that,,,, this is a real good upgrade, one to be proud of, to me it adds value as I am upgrade junkie, that includes old wire replacement. This garage is so small that I would toss most/all of it so it was obviously new and dont be scared to point at it to the insurance agent if he ever looks, staple neat and they would MUCH rather insure new wire.

 

Alright, here is what I now have:

• 65 feet of 2 gauge aluminum XHHW in red, black, and white. It was cheaper than THWN.
• 65 feet of 4 gauge aluminum XHHW in green.
• 60 feet of 1.5" PVC conduit
• Two 90 bends
• One LB to enter the garage
• One PVC bushing to join to the meter box

I'll also need to get a breaker to install in meter box.