[Tony Ankles]

Boss told me to order #2/3 AL NMD for a 100a sub panel feed from a 200a main panel for the upstairs suite. (Sub feed landed on a 2P100a CHOM breaker in the main with the sub panel having it’s own 100a main as well, also homeline).
my understanding of the CEC is if the equipment is rated for 75degrees that I must use the 75degree column of Table4 for selecting my wire which would bring me to #1 AL. Can’t really find anything in section 4 or 8 that would change this.
thanks in advance for any guidance here so I can stop spending my weekends reading the CEC.
Have a blessed day.

 

[u2slow]

There's basic ampacities, and then Table 39 for services. But this doesn't sound like a service.

 

[Ty the electric guy]

You are correct. Your boss is wrong.

 

[emtnut]

Pop in a 90A breaker in the Main Panel, and it's fine.

 

[Tony Ankles]

There's basic ampacities, and then Table 39 for services. But this doesn't sound like a service.

Table 39 is deleted in 2021 CEC but was wondering if since the job technically started over a year ago that they may have still been using 2018. It’s not a separately metered panel.

 

[Tony Ankles]

Pop in a 90A breaker in the Main Panel, and it's fine.

Yeah I’m definitely just overthinking it. #2/3 AL NMD is the largest size NMD Aluminium available (at least locally) otherwise we’d have to use ACWU. Which would be a bit more of a pain. 90amp breaker makes a lot more sense.
Thanks!

 

[Mike in Canada]

Yeah I’m definitely just overthinking it. #2/3 AL NMD is the largest size NMD Aluminium available (at least locally) otherwise we’d have to use ACWU. Which would be a bit more of a pain. 90amp breaker makes a lot more sense.
Thanks!

I love ACWU. By 'a bit more of a pain' are you referring to the armour on it? I suppose if you were trying to run it inside a wall it might suck to try to make the turns. I use it in an industrial setting, so it's probably a different thing for me.

 

[Tony Ankles]

I love ACWU. By 'a bit more of a pain' are you referring to the armour on it? I suppose if you were trying to run it inside a wall it might suck to try to make the turns. I use it in an industrial setting, so it's probably a different thing for me.

Totally yeah. It’s great just about everywhere except old wood studs and in situations where drywall/fishing is involved.

 

[eddy current]

Table 39 is deleted in 2021 CEC but was wondering if since the job technically started over a year ago that they may have still been using 2018. It’s not a separately metered panel.

A sub panel is not a service so it would not apply anyway.
(Ontario has a new table 39 in their 2021 code book)

 

[Phillipd]

Boss told me to order #2/3 AL NMD for a 100a sub panel feed from a 200a main panel for the upstairs suite. (Sub feed landed on a 2P100a CHOM breaker in the main with the sub panel having it’s own 100a main as well, also homeline).
my understanding of the CEC is if the equipment is rated for 75degrees that I must use the 75degree column of Table4 for selecting my wire which would bring me to #1 AL. Can’t really find anything in section 4 or 8 that would change this.
thanks in advance for any guidance here so I can stop spending my weekends reading the CEC.
Have a blessed day.

We do that too , the inspectors seem
ok with it . Recently we roughed in a house with a full in-law suite, 200A service with a 100A sub panel on the in-law suite. We fed the sub panel with 2/3al nmd and the inspector never questioned it.

 

[Tony Ankles]

A sub panel is not a service so

We do that too , the inspectors seem
ok with it . Recently we roughed in a house with a full in-law suite, 200A service with a 100A sub panel on the in-law suite. We fed the sub panel with 2/3al nmd and the inspector never questioned it.

on a 100a breaker?

 

[Phillipd]

on a 100a breaker?

That’s what we’ve been told to do also, I’m not saying it is code compliant with a 100A breaker instead of a 90 but the inspector passed it no issue or complaint.

 

[99cents]

That’s what we’ve been told to do also, I’m not saying it is code compliant with a 100A breaker instead of a 90 but the inspector passed it no issue or complaint.

And then the inspectors have a Monday morning meeting and are told to enforce the rule.

 

[Phillipd]

And then the inspectors have a Monday morning meeting and are told to enforce the rule.

Yup most likely

 

[Strider434]

There's basic ampacities, and then Table 39 for services. But this doesn't sound like a service.

Table 39 is deleted

 

[Wire2Wire]

Did the inspector even look at it?? By code it’s wrong.

 

[Sparkied]

Crazy my boss is the same way, must be the old school way of thinking still, he try’s using the wire temp rating column and never takes into account the termination temp. always been taught in school to refer to 4-004 termination temps and wire temp whatever’s lowest. So not sure if that’s how it was back in the day

 

[u2slow]

So not sure if that’s how it was back in the day

Termination temps used to be largely unmarked or disregarded.

 

[eddy current]

Crazy my boss is the same way, must be the old school way of thinking still, he try’s using the wire temp rating column and never takes into account the termination temp. always been taught in school to refer to 4-004 termination temps and wire temp whatever’s lowest. So not sure if that’s how it was back in the day

Back before 4-006 came out we only used the wire temperature rating.

What province are you in?

In Ontario you are still allowed to use the wire temperature when derating. Like 90 degree wire and a 75 degree termination temp, we can use the 90 degree value but only for derating using table 5 C and A

 

[Phillipd]

Did the inspector even look at it?? By code it’s wrong.

I’m not sure? The walls were all still open easy to look if he wanted