40 amp sub panel

[DonD]

Because of the wire size, I have to my garage, the biggest sub panel I can feed is 40 amps. here in Ontario I need a main breaker in it. I realize the rule is a little different in the States for small garage panels.
Problem is, I can’t find a panel with a 40 amp main breaker…60 amps is the smallest I can find.
I’ve done a lot of research and it appears the only way I can do it, by code, is by “back feeding”.
The back fed main breaker has to be held with a screw on clip, to prevent it from easily being easily pulled.
Does anyone have any experience with this arrangement? Do all companies have these kinds of clips for their load centres?

 

[afjes_2016]

I don't know the codes in Canada very well so won't comment on that;.
What I would suggest so when someone else reads this that may know the codes better that you also give us the brand/model # of the panel that will feed this garage circuit/panel.

Yes, some panel manufacturers do make tiedown kits. Square D is one of them.

 

[JoeD]

You don't need a 40 amp breaker in the sub panel. You need a 40 amp breaker in the panel feeding the sub panel.
Where are getting the info that you need a main in the sub panel? I am not aware of that rule.

 

[DonD]

You don't need a 40 amp breaker in the sub panel. You need a 40 amp breaker in the panel feeding the sub panel.
Where are getting the info that you need a main in the sub panel? I am not aware of that rule.

 

[DonD]

In Canada, we need a main breaker in a sub panel that’s in a separate building, such as a garage.…not if they are in the same building though.
I could be mistaken but I think it’s the same in the States, except for a garage with only 6 or 8 slots in the sub load centre.
I did some research and found some clips for breakers used to back feed, like in the picture, so I guess I just have to find a panel I can get a 40amp breaker and clip for.

 

[Snoonyb]

For clarification, which was not included;

However, the rule applies to "detached" structures, but not if the structure is attached, and considered a single unit.

 

[DonD]

For clarification, which was not included;

However, the rule applies to "detached" structures, but not if the structure is attached, and considered a single unit.

Yes, that’s what I understand. I have a detached garage that I meant to install a 60 amp load centre with a 60 amp main breaker. There was a miscommunication and #6 aluminum was buried, not #6 copper. I have to take responsibility for not being clear enough with the contractor and I wasn’t here when it was buried.
I have wired a lot of houses, myself, with no problems, with inspections, but never ran into this scenario. I think I better talk to inspector before I embarrass myself.

 

[DonD]

Yes, that’s what I understand. I have a detached garage that I meant to install a 60 amp load centre with a 60 amp main breaker. There was a miscommunication and #6 aluminum was buried, not #6 copper. I have to take responsibility for not being clear enough with the contractor and I wasn’t here when it was buried.
I have wired a lot of houses, myself, with no problems, with inspections, but never ran into this scenario. I think I better talk to inspector before I embarrass myself.

 

[DonD]

I did come across the above chart in the Canadian code and if I’m reading it correctly I can use 60 amp breakers.…see the asterisk under notes.

 

[Snoonyb]

Thanks. That should lead to clearer advise.

 

[PJB12]

You don't need a 40 amp breaker in the sub panel. You need a 40 amp breaker in the panel feeding the sub panel.
Where are getting the info that you need a main in the sub panel? I am not aware of that rule.

Don D's logo shows that he is in Canada.

CEC requires a main disconnect in the sub panel if the panel is not within sight of (and more than "X" number of meters from) the disconnecting means that is supplying power to the sub panel. (I forgot what the distance requirement shown as "X" above is.)

Correct at least as of last time I renewed my license in Ontario. I live in the U.S. and don't work in Canada since retiring, so I don't keep up with CEC changes.
Paul

 

[DonD]

Some further stuff on this 40 amp panel.
I have not been able to talk to an inspector yet but while researching I found these possibilities I can run past him. I want to appear that I know what I’m talking about.

1. I can use a 60 amp main breaker in the sub panel because the line to the garage is protected by the 40 amp feeder in the main panel. The one in the garage is simply a main shut off switch.
2. I can use a 60 amp main breaker in the sub panel if I’m using #6 aluminum Tech cable rated for 90°, which it is, if it’s used in “dry conditions”. I don’t think direct burial would be considered dry, but he may let me get away with it.
3. I can use a 40 amp back feed breaker in the sub, with the proper retaining clip.

I will see what he prefers and get back to you.

 

[bud16415]

I’m not sure if this will help and I’m not a licensed electrician.



There are 204V GFCI breaker disconnects in 40,50,60 amp ratings intended for hot tub/spa instillation as a sub-panel. Some I believe have 1-2 spare slots for use as 120V lighting circuits etc.



Could you use one of these to feed a panel that didn’t have the disconnect feature. It would give you the required 40 amp rating and also GFCI protection as required in a garage.

 

[DonD]

I’m not sure if this will help and I’m not a licensed electrician.



There are 204V GFCI breaker disconnects in 40,50,60 amp ratings intended for hot tub/spa instillation as a sub-panel. Some I believe have 1-2 spare slots for use as 120V lighting circuits etc.



Could you use one of these to feed a panel that didn’t have the disconnect feature. It would give you the required 40 amp rating and also GFCI protection as required in a garage.

I actually looked into that kind of breaker nippled into a bigger load centre, as you suggested, but those outside, hot tub GFCI tend to be pretty expensive.
I may need more than a couple of slots in the garage, especially if I want a 220v outlet in the future.

 

[bud16415]

I actually looked into that kind of breaker nippled into a bigger load centre, as you suggested, but those outside, hot tub GFCI tend to be pretty expensive.
I may need more than a couple of slots in the garage, especially if I want a 220v outlet in the future.

I have a 100 amp sub panel in my detached garage. It is about 100’ from the house. We bought this old house and I was pleasantly surprised when I saw how it was wired. Made it very easy to add air compressor and welder outlets and lots of power tool outlets in the workshop area. With just me working out there I will never come close to needing that all at once but is nice to have all the slots to be able to break up the circuits.



With just 40 amps you will also likely never need more, and I agree that a couple breakers wouldn’t be enough.



The other thing I keep in the back of my mind is will I be needing to charge an EV down the road. Even then it wouldn’t be that hard to juggle that with working in the garage.



I know the hot tub disconnects are a little pricey but given the 40amp requirement and the savings on the main panel being just a load center, I think I would probably do it. You would then have the GFCI covered right in the garage when you need to do a reset and the rest of the panel below it will all be covered.



Good luck and let us know how it turns out.

 

[DonD]

Thanks for your input. I don’t really plan on using it as a shop but I want to be prepared for the EV charging outlet and unknown future stuff.

 

[DonD]

Thanks for your input. I will let you know after I talk to the inspector.…probably after Christmas. I may also just put the 60 in, explain why I did it, and see what he says. I know him so he shouldn’t be too hard on me.

 

[PJB12]

Thanks for your input. I will let you know after I talk to the inspector.…probably after Christmas. I may also just put the 60 in, explain why I did it, and see what he says. I know him so he shouldn’t be too hard on me.

If you already have the 60 amp circuit breaker it won't hurt to try, but I doubt the inspector will allow it.

For less than 60.00 USD (about 80.00 CDN today's rate) you can buy the list below, if it will make your project quicker and more inspector-friendly:
100 amp 6-Space 12 Circuit Main Lug Load Center (No factory main)
2-Pole 40 Amp circuit breaker to serve as the garage main. (Ignore the main lugs.)
Breaker Retainer
Grounding Bar

Add 15.00 USD (About 20.00 CDN today's rate) and you can get a 20 space load center instead.

Be sure to bury your Teck90 Cable to meet CSA 12-012 and Table 53 requirements. Leave some trench exposed so the inspector can see that it's at the proper depth & laying on approved material.

I'd advise using anit-oxidant paste on the aluminum conductors where they terminate at both ends. Wire brush it in well.

Be sure that the main circuit breaker in the garage has the retainer that you wisely mentioned in Post #12

Enjoy Your Project!
Paul
PS: In my post #11, i made a typo. The distance is supposed to say "and/or", not "and". Also, as careless as I can be, I put the cool-guy electrician slang for CSA. I should have used the proper term "CSA" (instead of CEC) so everyone knows what I meant.

 

[garygnew]

I am in the states and am new to this forum, but am an engineer that designs electrical panels for industrial environments. Although the 60amp sub panel breaker is technically safe since there is an upstream 40 amp breaker, it has some practical issues. If anyone walks up to a 60 amp panel, they would assume it is capable of 60 amps, and may add circuits unaware of its smaller supply feed.... until they trip the upstream 40 amp. Then a homeowner who may NOT be knowledgeable on electrical wiring could easily assume that the 60 amp panel is correct and the 40 amp is undersized - and all they have to do is pop in a 60 amp breaker in the main panel and everything is good.

You would not do this because you know what you are doing, but an inspector has to look out for future owners who may not be as knowledgeable. If they do let you get away with it, they would probably require a label put on it indicating its feed source. Therefore, I would recommend against your option 1 of just using a 60 amp CB panel. Doing something non conventional causes confusion, and confusion is not good when dealing with electricity. I also would not do the "back-feed" breaker for the same reason. As for option 2, don't push it with the insulation even if you have the 90deg c rating. That just means that it can handle the extra heat without breaking down the insulation within a certain time period, but your wires will get still get hotter and could shorten the life of the insulation; ....however, I do think you can get away with a 50 amp breaker as long as you don't have the cheap wire... but let your inspector verify that.

Although those options aren't good, don't fret, because I think there is an easy solution. The requirement that there needs to be a separate panel/disconnect when it is in an unattached building is to prevent people from running circuits directly to devices (outlets, lights, etc.) from another building. I believe a main lug load center accomplishes the requirements even without a main circuit breaker. Each of the branch circuits would be protected and can be shut off from one location. I have attached a pic of the panel I would use. Run the feed wires right to the lugs then use the branch circuits. Put a label on the front that says "Fed from Main panel located on south wall of laundry room, circuit #12, 50 amp 240v" (or whatever your case is). That should satisfy all requirements. If they insist it has to have a single point disconnect rather than individual branch circuit protection, then just put an Air conditioner or spa unfused disconnect next to it. Those run about $15us.

Again, I work mainly with industrial electrical, which is a lot different than residential, and I wouldn't know all the codes for Canada, but hope this helps.

 

[garygnew]

just wanted to add more supporting info to my above post. The reason I believe a main circuit breaker in a sub panel is not needed is because you are coming from a branch circuit from your main panel to accomplish this requirement. I don't believe you need another one in the remote subpanel. If you came off the top of the main panel from the main leads, then you do need a main circuit breaker...but you are not doing that. I attached a pic to show what I am suggesting (only not 60 amps)

Also, PJB2 made a good point with coating the aluminum wires. Definitely do this even if the lugs say they are safe for AL. I use NOALOX.