Any electricians/electrically inclined here?

[Jswain]

I have a question about upgrading the breaker running to my garage from the current 40a to a 50a. I believe the wiring is all good to do so according to CEC but would like better verification.

It's a detached laned home garage. 100a main panel in basement, 8/3nmd90 ~30ft inside home. 8awg rw90 x3 in ~45ft conduit underground to garage. 8/3nmd90 inside garage ~20ft.

I believe 6/3 used to be what would be accepted until ~2012? And now 8/3 is acceptable because it is good for 50a @75c however reading the internet it's a 50/50 yes/no and although I did download a copy of the CEC it's so large and I have no idea which table to look at.

Home is in Cochrane, Alberta if it differs from province to province. Here's a photo for detached wiring for Airdrie which is about all I could find but makes me believe 50a is acceptable with the nmd90/rw90 combo

 

[Darren]

In reality it will be fine, but are you wanting to switch the breaker due to nuisance trips? If so, try it, if it still trips you'll need new feeder wires anyway.

If not due to tripping, don't bother. It doesn't increase power to the garage or anything...

 

[Jswain]

In reality it will be fine, but are you wanting to switch the breaker due to nuisance trips? If so, try it, if it still trips you'll need new feeder wires anyway.

If not due to tripping, don't bother. It doesn't increase power to the garage or anything...

Yes it has been fine thus far, but last year I got a precision Tig 225 and welding aluminum it trips the 40a. Which contaminates everything and only happens in areas you can't get a tool in to clean(of course)

I already have tried a 50a and I can easily weld without tripping, however i just want to double-check it's 100% ok

Just another note welder circuit in garage is currently equipped with a 40a breaker as well. Which I would like to change to 50a if that is acceptable too. It is wired with ~4ft 8/2. If I can't have 2 of the same breakers inline I will leave the 40a in the garage

 

[Tom Kitta]

Oh for a welder? Yes its 100% fine - I bet your welder duty cycle is not 100% when breaker kicks - its less. Maybe duty cycle is like 60%. You use that in your calculation.
There is an exception in the rules for "duty" machines.

Yes you can totally have same breakers in both garage and the house. For the breaker box in the garage you can have larger breaker than the line permits - i.e. say 200 amps. Its OK as it is no longer serving as a breaker but a cut off.

Just use common sense.

Regarding the temp ratings, you would need everything rated for higher temp to use that. My limited experience says that especially older inspectors don't like the temp stuff - they also don't like some other stuff and you need to just point to the rule for them to reluctantly agree.

For a welder, duty cycle is the name of the game. Same for compressor.

 

[Jswain]

I know a little bit about the welder circuit and allowing to oversize the breaker, but the breaker in my house is for the garage feeder.

Wanting to know if 8/3 nmd90 & 8awg rw90 is acceptable to use with a 50a breaker for a detached garage

If not I will use it as a "welder circuit" put the wires on the 50 when needed for welding aluminum and back to the 40 for everyday use, but obviously would be better if I don't have to do that.

Good to know I can use a same sized breaker in garage and on feeder though thank you, the more I read the more controversial it gets

 

[Tom Kitta]

OK got it, its a garage feeder and you wonder if you can use 75 degree for 50 amps.

You can as long as everything is rated 75 degrees or more in your whole setup. I.e. all panels, breakers, cables etc.

If the rating is not specifically stated its == 60C since you are under 100 amps.

Also note there does not seem to be anything rated 90 degrees.

 

[Jswain]

Ok I will look into that. Thank you

 

[Dabbler]

OK, so here goes. This is my read. If you are going underground you need to use NMWU in the PVC pipe. To go to more than 40 amps you need to replace the 1.25 inch PVC to 1.5 inch PVC and pull NMWU 6 gauge wire.

That is what it says. You cannot use NMD90, as it appears it is no longer approved for underground use. My 6 gauge NMD90 installation is grandfathered - installed by a professional and inspected in 1995 (about)...

If I make any change to the circuit - I would have to repull NMWU in that conduit. I future proofed by installing a 3" conduit, which the inspector griped about, but there was no statute preventing the larger pipe. My feed is 60 amps.

 

[Jswain]

OK, so here goes. This is my read. If you are going underground you need to use NMWU in the PVC pipe. To go to more than 40 amps you need to replace the 1.25 inch PVC to 1.5 inch PVC and pull NMWU 6 gauge wire.

That is what it says. You cannot use NMD90, as it appears it is no longer approved for underground use. My 6 gauge NMD90 installation is grandfathered - installed by a professional and inspected in 1995 (about)...

If I make any change to the circuit - I would have to repull NMWU in that conduit. I future proofed by installing a 3" conduit, which the inspector griped about, but there was no statute preventing the larger pipe. My feed is 60 amps.

Sorry it isn't a new install. Installed already as built by the builder. 8/3 nmd90 in the house & garage, 8awg x3 rw90 underground in conduit. Just they used a 40a breaker and from what I can find is that it should be acceptable for me to install a 50a breaker.

They say in the same pdf that isn't the only acceptable method (nmwu underground) but they don't list the others.

The rw90 is definitely acceptable for underground, and from what I can tell also good for a 50a breaker because it's rated for 90 degrees like the NMD90 vs 60 degrees for the nmwu. But they don't want you using 90 degrees ratings so at 75 they should both be good for a 50a breaker?

I guess this is why they make electricians . It's a harder topic to search because 9/10 you get info from south of the border

 

[Susquatch]

Good to know I can use a same sized breaker in garage and on feeder though thank you, the more I read the more controversial it gets

I'm not 100% sure I understand your question.

Are you asking if a 50A breaker will work or if swapping in a 50A breaker will meet code?

I think everyone is agreeing that it will work. In my opinion, it will be fine for two reasons: 1. the built in safety factor and 2. It's a welder that is causing you problems and therefore duty cycle will reduce the system load while the 50Amp breaker will stop trips.

If you are asking if it will meet code, then I can't say. Almost every inspector has their own prejudices. It boils down to their individual preferences. In any event, just call them and ask!

If you don't plan on getting a permit, then I'd just do it. If you do, then ask. It's really that simple.

 

[Jswain]

I'm not 100% sure I understand your question.

Are you asking if a 50A breaker will work or if swapping in a 50A breaker will meet code?

I think everyone is agreeing that it will work. In my opinion, it will be fine for two reasons: 1. the built in safety factor and 2. It's a welder that is causing you problems and therefore duty cycle will reduce the system load while the 50Amp breaker will stop trips.

If you are asking if it will meet code, then I can't say. Almost every inspector has their own prejudices. It boils down to their individual preferences. In any event, just call them and ask!

If you don't plan on getting a permit, then I'd just do it. If you do, then ask. It's really that simple.

Asking if changing to a 50a breaker would meet code.

The part you quoted I was wondering if I can have a 50a breaker in the house feeding the garage to the garage subpanel and then in that garage subpanel a 50a breaker for the welder, which from more reading seems perfectly fine.

Not planning on getting a permit if all I have to do is swap a breaker, as long as what I'm doing would meet code, which is why I asked.

 

[Tom Kitta]

The rw90 is definitely acceptable for underground, and from what I can tell also good for a 50a breaker because it's rated for 90 degrees like the NMD90 vs 60 degrees for the nmwu. But they don't want you using 90 degrees ratings so at 75 they should both be good for a 50a breaker?

I guess this is why they make electricians . It's a harder topic to search because 9/10 you get info from south of the border

The 90 degree cable rating is meaningless as almost nothing residential supports 90 degrees.

The deal is in the contactor - you need contactor rating.

Personally I do not know why you care so much about this - your welder is not going to pull that current for hours on end. Does someone else has access to this and can go crazy?

 

[Dabbler]

Sorry it isn't a new install. Installed already as built by the builder. 8/3 nmd90 in the house & garage, 8awg x3 rw90 underground in conduit. Just they used a 40a breaker and from what I can find is that it should be acceptable for me to install a 50a breaker.

You don't understand what I'm saying. If you rewire anything in the circuit - including changing the circuit breaker - it has to be brought up to code. Changing the value of the circuit breaker is enough to trigger this section of the CEC.

I know that this isn't what you want to hear.

But if 'something happens', this gives an insurance company license to refuse to cover. One could hypothesize that the breaker was *as installed* at 50 amps. But some insurance fellows are very clever blokes. *If* the original electrician installed 50 amps, using NMD90, then you could easily replace a faulty with an equivalent breaker.

Here is what I would reason in the matter. The update to the CEC was done for a reason. The requirement for the NMWU is probably safer. If I was sure that my installation is safe, I'd probably upgrade, and then downgrade back if I were to sell the house. However, I pulled my wire in a 3" conduit so I could pull safer wire when the code changes, if I had to change anything, so I prefer overkill to marginal wiring.

The inspector also griped about me pulling 6Ga wire instead of 8Ga - but the wire was legal, and he couldn't bounce me for it. -- Yes I pulled the wire and installed the box and installed the conduit. THEN I had my electrician do all the hookups and check my work.

I've done quite a few wiring jobs with several contractors, in both industrial and domestic applications. They use me as raw labour, wire pullers, and installers, including terminating connections - but a licensed electrician always checks my work, just like any apprentice. I started wiring with my dad in the 1960s, and have kept my hand in ever since. I just never wanted to be an electrician full time.

 

[Tom Kitta]

You don't understand what I'm saying. If you rewire anything in the circuit - including changing the circuit breaker - it has to be brought up to code. Changing the value of the circuit breaker is enough to trigger this section of the CEC.

I know that this isn't what you want to hear.

But if 'something happens', this gives an insurance company license to refuse to cover. One could hypothesize that the breaker was *as installed* at 50 amps. But some insurance fellows are very clever blokes. *If* the original electrician installed 50 amps, using NMD90, then you could easily replace a faulty with an equivalent breaker.

Here is what I would reason in the matter. The update to the CEC was done for a reason. The requirement for the NMWU is probably safer. If I was sure that my installation is safe, I'd probably upgrade, and then downgrade back if I were to sell the house. However, I pulled my wire in a 3" conduit so I could pull safer wire when the code changes, if I had to change anything, so I prefer overkill to marginal wiring.

The inspector also griped about me pulling 6Ga wire instead of 8Ga - but the wire was legal, and he couldn't bounce me for it. -- Yes I pulled the wire and installed the box and installed the conduit. THEN I had my electrician do all the hookups and check my work.

I've done quite a few wiring jobs with several contractors, in both industrial and domestic applications. They use me as raw labour, wire pullers, and installers, including terminating connections - but a licensed electrician always checks my work, just like any apprentice. I started wiring with my dad in the 1960s, and have kept my hand in ever since. I just never wanted to be an electrician full time.

"Rules 4-008 Insulated Conductors Types of Conductors Acceptable for Direct Earth Burial Direct buried conductors in contact with the earth are to be of the types listed in Table 19. Conductors installed underground in a protective raceway, or plastic pipe, are not considered to be in contact with the earth, therefore types such as RW75, RW90, TW or TW75 listed in Table 19 for use in "wet locations" are acceptable."

https://www.calgary.ca/content/dam/www/pda/pd/documents/building/ampacity-of-wire-and-cable-for-underground-installations.pdf

I.e. if he is in Calgary RW90 are acceptable.

Thus he does not need to bring anything up to code.

BUT, I am not sure about the permit part as you do not need a permit when replacing a breaker with the same type and size. But you are not replacing with the same size.

 

[Susquatch]

Asking if changing to a 50a breaker would meet code.

The part you quoted I was wondering if I can have a 50a breaker in the house feeding the garage to the garage subpanel and then in that garage subpanel a 50a breaker for the welder, which from more reading seems perfectly fine.

Not planning on getting a permit if all I have to do is swap a breaker, as long as what I'm doing would meet code, which is why I asked.

I still see this really simply.

You say you want to meet code. You say you won't do anything not to code.

Therefore you have nothing to lose by calling your inspector. He will be the last word on this anyway so you might as well call him. I see no downside to doing that.

 

[Dabbler]

@Tom Kitta -you make my point. RW90 is the equivalent (or much closet to) of NMWU, not NMD90, and has lower peak capacity.

Hey, if the inspector okays it, then that's great! So I'm +1 on the call to the electrical inspector. I'm always looking to learn...

 

[Jswain]

@Tom Kitta -you make my point. RW90 is the equivalent (or much closet to) of NMWU, not NMD90, and has lower peak capacity.

Hey, if the inspector okays it, then that's great! So I'm +1 on the call to the electrical inspector. I'm always looking to learn...

I guess that's the true question. Is the rw90 good for the 50a breaker as per CEC.

According to its spec sheet it's good for 50a @ 75c in conduit versus 8/3 nmwu which is only good for 40amps(because it's only rated for 60c) on Southwire specs sheet so I would have presumed it was similar to the nmd90 ratings.

 

[Jswain]

So for some closure I decided to go ahead and throw a 50a in the garage feeder & also a 50a in the welder circuit. I checked all the connections between the two to ensure everything was good and ran an amp clamp on he circuit with each item in the shop in use.

Heater draws ~21amps

Compressor draws ~23amps @ cutout

Tig Welder....boy she's a thirsty one.
At 230amps(max) she OL the 100a setting(max) on my amp clamp lol
At 200amps it draws ~98amps
At 150amps it draws ~77amps

Mig welder draws ~56amps on just about maxed settings

A little worried I decided to test out the Tig and see how long it takes to trip the breaker. Welding at 200amps I burned two full rods of filler which was ~ 8x 4" welds, nearly back to back and it never tripped at all. I feel like I could have easily ran the machine into its duty cycle without tripping(success). After this I checked the temp of the 8awg conductors in the garage and the temperature was still around ambient.

No doubt why they recommend a 50a breaker min. and 70a preferred though. Hopefully this combo will work out well enough for me, if not I will report back.

I always shut the compressor off when I'm not in the garage, the heater does stay on, with a thermostat and never seems to run more than maybe a 30% duty cycle so I'm thinking everything will be kosher. Thanks for the help!