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Service Entrance Main Breaker Revamp

8K views 21 replies 4 participants last post by  nap 
#1 ·
In '98 we purchased a house (built in '73) and have been renovating ever since. The homes in my neighborhood were originally built in an unincorporated are of the county and must not have been subject to any inspections at all based on the (lack of) quality of workmanship and materials used.


A few summers back my main breaker (100A) failed on a Friday afternoon leaving us without power. Since the box was a Federal Pacific the electrician told me it would be cheaper to go to HD and buy a GE box to replace it than trying to find a replacement main. I asked him about upgrading my service and he told me the existing cables to the meter were large enough to install a 125 amp box. So he removed the meter to cut power and I replaced the 100A outdoor box with a 125A indoor box over the weekend while the family swam and watched movies at a local motel. I put the new box inside because the original box was on a south wall and had problems overheating during the summer and would trip the AC breaker. The electrician came back on Monday and hooked the power back up and I also had him look over my work to make sure everything was safe.


Now I want to revamp the service entrance to bring it up to code and make it neat and easy to maintain. The existing indoor box does not have adequate (required) working space clearance and was hastily (kinda sloppy) installed. The circuits are not up to code in regards to GFCI/AFCI protection, required dedicated circuits, and quality of workmanship. The grounding needs to be expanded with several more rods. The U/G feed to the garage subpanel need to be replaced with the proper cable for wet environment. An so on and so forth, blah, blah, blah.

Here is the existing service entrance:


 
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#10 ·
The 10/3 that goes outside into the conduit LB is an indoor cable. Is it spliced to a different wiring method inside of the LB? .....
Yes, it's the wrong type - it will be replaced with #6 SER (or #4 - whatever the calcs require to allow for voltage drop) for 60 amp garage subpanel. The existing conduit is 3/4". I may need to run a larger conduit.
FYI, you can not install SER cable into an underground conduit. All you need to do here is make the conduit continuous from one enclosure to the other, and then install three #6 THWN conductors, with a #10 ground. The conduit is large enough for those wires.
 
#11 · (Edited)
FYI, you can not install SER cable into an underground conduit. All you need to do here is make the conduit continuous from one enclosure to the other, and then install three #6 THWN conductors, with a #10 ground. The conduit is large enough for those wires.
Thanks for catching that! It does seem odd it would not be allowed since it is rated for wet locations. (code ref 310.10.C.3 listed for use in wet locations, 310.15.B.7 type SE cable allowed for feeders, VERY STRANGE - table 310.104(A) construction specs, doesn't even list type SE)

Found it! 338.12.2 SE not allowed ug with or without a raceway.

As far as making the conduit continuous, where is that in the code? I'd like to know for future reference. I searched and searched but could not find any requirements to make it continuous, only to protect it where subject to physical damage. (code ref 300.12 exc #1 short run used for support or protection only)

I'm not doubting you, it's just I like to know where the requirements are in case I need to access then again. Thanks.
 
#3 · (Edited)
The new panels will have to go on the opposite wall from the existing. It is the nearest to the service entry point I can get and have the required clearance. I have already placed the first new panel. It is a 125A Cutler-Hammer main lug box. I intend to connect it to the existing box temporarily with a 50A feeder (6/3 NM) and install the circuits that have already been upgraded during the course of the house renovation. Then I will install a 125A outdoor main service disconnect and new 125A MB panel with a appropriate subpanel feed to the already installed subpanel.




The new MB panel will go to the right one stud space over to allow clearance for the covers. Why two panels instead of one? It was cheaper than ordering a convertable panel and HD didn't sell a larger panel with 125A MB.

I intend to connect the service entrance>main disconnect>main breaker panel with #2 SER (copper). I think I only need to protect the SER from physical damage with conduit until it is inside the wall - not all the way to the MB panel from the main disconnect.

Any thoughts, questions, comments, suggestions so far?
 
#6 · (Edited)
2/0 copper is large enough for a 200 Amp service. You only need a #2 copper for a 125 Amp service.

Your (existing) neutral wire lacks proper marking with white tape (or paint).

The 10/3 that goes outside into the conduit LB is an indoor cable. Is it spliced to a different wiring method inside of the LB?
 
#7 ·
That leaves one spare space for any future needs. I may need to order a bigger main panel..
I wouldn't even hesitate. Put it in now while you are doing all of this.



the old panel is going away, right? how are you getting from that spot to the new panels? if you are putting a junction box in place of the old panel, be mindful of box fill. How will you get all of the circuit conductors over to the new panels?



how much room do you have between the wall (the panels are going in) and anything such as the washer and dryer, shelf up above that would be in the 30" width space for the panels? Looks a bit shy but hard to tell in a picture.
 
#9 ·
I wouldn't even hesitate. Put it in now while you are doing all of this.
I agree. I'm only doing this once.

the old panel is going away, right? how are you getting from that spot to the new panels? if you are putting a junction box in place of the old panel, be mindful of box fill. How will you get all of the circuit conductors over to the new panels?
Yes, the existing box is going bye bye. I'm pulling all new cable in the attic to the subpanel first and then to the new (larger) main panel. The new service disconnect will go outside where the original box was (opposite the existing panel).

how much room do you have between the wall (the panels are going in) and anything such as the washer and dryer, shelf up above that would be in the 30" width space for the panels? Looks a bit shy but hard to tell in a picture.
36" to the washer/dryer. The shelf above will be deleted.

I appreciate your comments. I'll take a few pics of the attic space tomorrow to post and show the existing wiring.
 
#12 ·
he is saying to use a different type of wire that requires conduit. If conduit is used merely for localized protection, it does not need to be continuous. Obviously, if it is used as a conduit system, it would have to reach from here to there.

I got a bit lost with kbsparky and the underground conduit. Did I miss something? :huh:


the allowances and disallowances will be found in art 338.10 and 338.12
 
#13 ·
he is saying to use a different type of wire that requires conduit. If conduit is used merely for localized protection, it does not need to be continuous. Obviously, if it is used as a conduit system, it would have to reach from here to there.
Would this apply and how does this fit in with previous comments?

300.5.D.2 Wiring Methods -Underground installations - Conductors entering buulding - ...shall be protected to the point of entrance
 
#14 ·
As far as the panel is concerned, you can install a 200 amp rated main lug panel as long as you install the 125 amp breaker outside.
This will give you all the spaces you need now and the furture.
 
#15 ·
I'm glad you mentioned that (see below). I wanted to avoid having the main breaker outside so I intended to install a main disconnect switch and keep the breaker inside on the main panel. But I could use the 125A main lug panel as my main panel with the breaker backwired and add the 200A lug panel as a subpanel. How does that sound?

:whistling2:My duh moment: I've spent the last week researching panels and just realized a 200A panel is rated up to 200 amps, not 200 amps only.:laughing: Oh well, that why it says "knothead" in my avatar...
 
#16 ·
HD doesn't sell 200A main lug panels, but I did luck out and find a 125A 24/24 main lug at the third HD I went to. That will give me twice the spaces I had with the 12/24 which should be adequate with several spaces left for future expansion if required.
 
#20 ·
Not sure what the dispute is here. If the cable being used does not require a conduit system, you do not have to have a continuous conduit system. You can protect only the section that needs protection.

if you use a wire or cable that must be in conduit, it simply has to be continuous from j box (or whatever) to j box (or whatever)


I think the miscommunication came in where KB said the NM or the SE cables are not allowed underground and further suggested simply making the conduit system complete and use THWN.

after that, the entire conversation kind of went to Hell:laughing:




thanks KB. For some reason I was not associating that conduit with the conduit outside that goes into the ground.
 
#21 ·
Not sure what the dispute is here. If the cable being used does not require a conduit system, you do not have to have a continuous conduit system. You can protect only the section that needs protection.

if you use a wire or cable that must be in conduit, it simply has to be continuous from j box (or whatever) to j box (or whatever)


I think the miscommunication came in where KB said the NM or the SE cables are not allowed underground and further suggested simply making the conduit system complete and use THWN.
All that makes sense to me.

after that, the entire conversation kind of went to Hell:laughing:.
Not sure what you mean here. For my part I have no problem with anything said and appreciate everyone's input.:thumbsup:
 
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