Wire size from disconnect to panel?

[Papisox]

Hello, I have 250 aluminum coming from transformer to disconnect inside house. 200a Panel will be 25’ away. What size wire should be used from disconnect to panel?

 

[tom baker]

This appears to be a DIY post which we can not answer due to forum rules.

 

[Papisox]

It’s not a DIY post. My builders electrician was running what I thought to be an undersized wire to panel, and looking for opinions.

 

[tom baker]

It will have to be answered by someone familiar with CEC.

 

[tom baker]

What size was installed?

 

[Papisox]

It hasn’t been installed yet, he’s supposed to install Monday, that’s why I was hoping to get opinions to speak with him

 

[kwired]

It will have to be answered by someone familiar with CEC.

That is absolutely true for OP.

Per NEC there are conditions it possibly could appear to be undersized but still be code compliant, but many details can be a factor, including overcurrent protection setting(s), overcurrent protection location(s) conductor installation/routing details (what is considered inside vs outside), and of course basic conductor ampacity rules in general.

If what is in question is considerably smaller than the 250 aluminum supply but has 200 amps or protection chances are his thinking it is undersized may be valid. If it is only slightly smaller, there could be reasons it is still acceptable. If it is copper instead of aluminum it could possibly be smaller than OP may think is allowed and still be legal.

 

[Dennis Alwon]

I believe the CEC is similar to NEC in wire size. IMO, it would be 4/0 aluminum at the minimum. It may also require 250 kcm.

What size is the electrician running? Isn't the job getting inspected?

 

[fishin' electrician]

My builders electrician was running what I thought to be an undersized wire to panel...

It hasn’t been installed yet...

 

[kwired]

I believe the CEC is similar to NEC in wire size. IMO, it would be 4/0 aluminum at the minimum. It may also require 250 kcm.

What size is the electrician running? Isn't the job getting inspected?

He didn't give enough details to confirm anything though. That would cover what is likely majority of time with what little info we have.

If they happen to change over to copper inside it could be even smaller conductors.

 

[Papisox]

He is saying 2/0 copper to the panel. Yes it is a new build being inspected, and we have permit. I’m sure the inspector will tell him if undersized, I was just asking a question.

 

[electrofelon]

2/0 copper could commonly be the proper size for a 200A dwelling service or feeder here in the states.

 

[tortuga]

See table 2 of the CEC,
especially note ††

For 3-wire 120/240 V and 120/208 V service conductors for single dwellings, or for feeder conductors supplying
single dwelling units of row housing of apartment and similar buildings, and sized in accordance with
Rules 8-200(1), 8-200(2), and 8-202(1), the allowable ampacity for sizes No. 6 and No. 2/0 AWG shall be 60 A
and 200 A, respectively. In this case, the 5% adjustment of Rule 8-106(1) cannot be applied.

my version is pretty old now but I don't think its changed.