DIY Home Improvement Forum banner

1 - 13 of 13 Posts

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #1
HI Guys,
Should be a simple one here, Just want to run this past you to make sure I didn't miss anything and that this will all be approved.

I ran 3/4" EMT from my panel in my basement to the attic space above the kithen. I am planing to install a small-ish 22 space CH panel. Primarly to feed the kitchen lights, and outlets, along with feeding the bathrooms when I replae the wiring to them. The stove / espresso machine will be fed from the basement, so this panel will mainly see lighting and counter top appliances.

I am planing to run 4 - 6AWG wires to the panel, seperating all neutrals and ECG. I am planing on proteting the panel with a 70A breaker in the main panel. Per 310.16 - 6 AWG THHN is rated for 65 A @ 75 degrees, and since your allow to round up, I was going to use a 70A breaker.

Please let me know if any of the above sounds incorrect.

The only question / concern I have is that this attic space is fully insulated, but unheated. It gets no where near as cold as the top (above the 2nd floor uninsulated attic) nor as warm, however it is not climate controaled directly. Do I need to de-rate the wire capicity due to the warmer temperatures it will experiance in the summer?

Thanks very much. I made a lot of progress with EMT runs yesterday.
Jamie
 

·
Super Moderator
Joined
·
20,886 Posts
60 amp is max for #6 wire. All parts of the system must rated 75ºc for that rating to apply. The breakers, the panel lugs are probably only rated 60ºC.
 

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #3
60 amp is max for #6 wire. All parts of the system must rated 75ºc for that rating to apply. The breakers, the panel lugs are probably only rated 60ºC.
After I posted, I started thinking about it, and wondered if this would be a problem.

The wire would run between 2 brand new Cutler Hammer CH panels. The breakers say: "Use 60 / 75 degree wire". These are the only 2 things that the wires would be connected to (one new panel to the other new panel).

I will go onto cutler hammer and see if they say anything about this. However since both breaker say use 60 / 75 degree wire, I would assume that would mean they are both rated for 75 degree wire maxium?

Jamie
 

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #4
I've looked at all the online spec sheets for cutler hammer CH series panels and breakers, and everything I find says Suitable for use with 60 or 75 degree wire.

So is there any reason not to use the 75 degree rating and run 70 AMP?

Jamie
 

·
Registered
Joined
·
1,013 Posts
Am I understanding this correctly? You want to install a subpanel in the attic space? What happens when you trip a circuit? I don't think its a good idea or is allowed to have a sub panel in the attic space. I could be wrong, but to me that doesn't seem like a good idea. I would maybe try and locate it in the basement or other interior wall that would be much more accessible.
 

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #6
Am I understanding this correctly? You want to install a subpanel in the attic space? What happens when you trip a circuit? I don't think its a good idea or is allowed to have a sub panel in the attic space. I could be wrong, but to me that doesn't seem like a good idea. I would maybe try and locate it in the basement or other interior wall that would be much more accessible.
It is a walk in attic with a full size access door at the top of the stairs, located directly above the kitchen. It is atleast as easy to access as anything in the basement would be.

The attic has some walk around height to it, It is almost 89" at the inside wall, and then lessens as the roof pitches. There is more than enough clearance left to right, and about 89" floor to rafters where the sub panel would be located. There would be about 25" from the left side of the panel to the door that allows access to the attic, and on the right side of the panel, there would be about 30' of wall space at that same height.

Thanks
Jamie
 

·
Registered
Joined
·
1,013 Posts
Ah, ok that makes sense then. Sorry I was thinking of an attic space with lots of insulation and barely enough room to walk through the attic. I wish the attic at the house here was that big, would make running Ethernet cable a whole lot easier. That and falling through the ceiling isn't likely to happen with I am assuming plywood floors. Yes I did fall through the ceiling once, nearly tried to make a skylight in the living room, lol. Ripped the RG6 cable that I ran for the cable/phone modem in two, missed a cabinet and fell to the floor with out getting injured. That was lucky haha.
 

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #8
Ah, ok that makes sense then. Sorry I was thinking of an attic space with lots of insulation and barely enough room to walk through the attic. I wish the attic at the house here was that big, would make running Ethernet cable a whole lot easier. That and falling through the ceiling isn't likely to happen with I am assuming plywood floors. Yes I did fall through the ceiling once, nearly tried to make a skylight in the living room, lol. Ripped the RG6 cable that I ran for the cable/phone modem in two, missed a cabinet and fell to the floor with out getting injured. That was lucky haha.
Yes, about 9' for plywood flooring that run the legenth of the attic space, so there is some open floor space, but that is only where it is about 3' high from the floor to the roof, so you are not likely to fall through it.

I have the floor ripped out in the kitchen, working on replacing it. When I was ripping it out, the cord on a saw got caught and I triped, and fell between the (16 o.c.) joists thought the ply wood ceiling in the basement, Caught myself on the way down, hanging half way thought the broken basement plywood ceiling. Ouch that one sucked.

I am going to throw in a wire chase before some of the downstairs walls get closed back up so I can easily pull network cable if I need to, I use wireless all the time, so I don't have a lot of need for hardwire. I think I am getting one of those Sling box things that you connect to your TV, so I am going to have to run some cat 5e or something...

Take care
Jamie
 

·
Phil
Joined
·
58 Posts
Difficult to see what you gain with a subpanel in the attic as compared to a subpanel in the basement. Your runs to the appliances will be longer which is the opposite of what you want to accomplish with a subpanel.

With a subpanel in the kitchen level you can run a single heavy gauge wire from the main and then have shorter runs to the lights and wall outlets as well as to the oven and cooktop, dishwasher, garbage disposal etc. and in so doing save electricity and better balance loads.

I would spend the money to get an electrical contractor or two in to look at your existing setup and make recommendations. They bring a lot of practical experience that you lack and the cost of their advice is nominal.
 

·
Registered
Joined
·
1,802 Posts
Difficult to see what you gain with a subpanel in the attic as compared to a subpanel in the basement. Your runs to the appliances will be longer which is the opposite of what you want to accomplish with a subpanel.

With a subpanel in the kitchen level you can run a single heavy gauge wire from the main and then have shorter runs to the lights and wall outlets as well as to the oven and cooktop, dishwasher, garbage disposal etc. and in so doing save electricity and better balance loads.

I would spend the money to get an electrical contractor or two in to look at your existing setup and make recommendations. They bring a lot of practical experience that you lack and the cost of their advice is nominal.
I'm interested in saving electricity this way. Can you explain how that works?
 

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #11
Difficult to see what you gain with a subpanel in the attic as compared to a subpanel in the basement. Your runs to the appliances will be longer which is the opposite of what you want to accomplish with a subpanel.

Hun? Why would my runs from the attic be longer than they would in the basement? The half of the basement under the kitchen is finished. The only good area in the basement to have a sub panel is near the current panel, which is a 50 foot run to the kitchen. Vs the panel located 4' above the kitchen ceiling then droped 4' to the switches or outlets, plus a bit of extra wire for routing. This make my drops closest to the attic panel maybe 12' to 15 feet, and the farest runs maybe 30'.

What am I missing how is this the oppsite of what I want to accomplish?

The heaviest draw appliance will be the oven, which will be 8 or 10awg, and I will run a piece of emt to the oven from the main panel.

With a subpanel in the kitchen level you can run a single heavy gauge wire from the main and then have shorter runs to the lights and wall outlets as well as to the oven and cooktop, dishwasher, garbage disposal etc. and in so doing save electricity and better balance loads.

This is NOT new construction. How would I route wires / conduit if I had the panel board on the kitchen level? The only way to access the room without ripping out all the walls is to fish down from the attic or fish up from the basement.

Can you please explain how I can balance loads ot save electricity. That meter on my house seems to measure in KWH, which measures all the power you use, regardless of where or how it is used.

jamie
 

·
Phil
Joined
·
58 Posts
I would expect that your current kitchen lighting including the oven circuit are run off your main panel. You are putting in a subpanel and yet still running a new wire to the oven from the main that is further away than where you plan to have the subpanel makes less sense than running a new heavy gauge line from the service panel to the new subpanel and powering your kitchen off that additional service rather than working within the confines of your existing service and panel.

In terms of KWH usage there are line losses with distance. That is why heavier gauge wiring is required for both higher amperages, and with extension cords with additional length. The line loss from the resistance of the conductor is in the form of heat, hence the fire risk if it is great enough, but current loss at all times which does make it through your service panel and meter but does not make it to the electrical appliance.

With the addition of high power microwaves, toaster ovens, coffee makers, etc. many kitchens have insufficient amperage on their supply circuits and you can juggle the loads for your house but it is better in the long run to add amperage with additional service and a subpanel. Your project seems to only go half way.
 

·
DIY'er
Joined
·
2,044 Posts
Discussion Starter #13
I would expect that your current kitchen lighting including the oven circuit are run off your main panel. You are putting in a subpanel and yet still running a new wire to the oven from the main that is further away than where you plan to have the subpanel makes less sense than running a new heavy gauge line from the service panel to the new subpanel and powering your kitchen off that additional service rather than working within the confines of your existing service and panel.

In terms of KWH usage there are line losses with distance. That is why heavier gauge wiring is required for both higher amperages, and with extension cords with additional length. The line loss from the resistance of the conductor is in the form of heat, hence the fire risk if it is great enough, but current loss at all times which does make it through your service panel and meter but does not make it to the electrical appliance.

With the addition of high power microwaves, toaster ovens, coffee makers, etc. many kitchens have insufficient amperage on their supply circuits and you can juggle the loads for your house but it is better in the long run to add amperage with additional service and a subpanel. Your project seems to only go half way.
Ok I see, you were simply suggesting to run the entire kitchen off of the sub panel? This is more of an issue of logistics rather than one of electrical design. As the drops to counter top outlets, microwave, range hood, lighting are easily accomplished from the attic through the kitchens sofit box system. However run back down to the floor and up to the Stove and coffee bar are not easy at all, It would mean opening more walls and drilling more joists to get runs form the attic panel back down to the oven / coffee bar, vs pretty easy runs to the basement panel.

With 6awg running to the attic panel, then fairly short drops to the lighting and outlets, I should deffinatly see less voltage drop in the kitchen vs doing home runs back to the panel.

6awg to the sub gives me 60 amps on each leg, 120a service to the 120 outlets in the kitchen. That's a pretty huge amount of power for 120 appliances to draw. I have to try really really hard (running a stupid number of resistance appliances, heatguns, heaters, etc.) to see 60a per leg on my main.

When you say:

"many kitchens have insufficient amperage on their supply circuits and you can juggle the loads for your house but it is better in the long run to add amperage with additional service"

Are you saying that 20a service is inadequate for most kitchen circuits? Adding amperage, are you saying that my service drop should be upgraded to support the kitchen? I am not sure I am following you?

Thanks for your assistance. I am going to try and work on some more of the 3d renderings for the kitchen later today and will upload some once I get the electrical added into the model. It will make it much easier to see what is going on.

Jamie
 
1 - 13 of 13 Posts
Top