Leonan
Member
- Location
- Massachusetts
- Occupation
- Electrician
Hi everyone, I did a 400A service in MA and the inspector asked to use 800kcmil aluminum wire, but in code 310.12 I can use 600cmil. Am I right?
Service size
- Thread starter Leonan
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If not for a dwelling you can use 750 kcmil AL if the calculated load is 385 or less.
Leonan
Member
- Location
- Massachusetts
- Occupation
- Electrician
Yes. 120/240 single phase, a dwelling.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Then you'll need a minimum conductor rated at 83% of 400 amps.
zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
Does anyone sell or use 800kcmil (it's in the size charts)? I don't think I've ever seen larger than 750, get larger than that and it smaller sizes doubled.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Almost 40 years never installed anything larger than 750 kcmil.
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
Parallel runs of 4/0 aluminum work * As long as the load is less than 360A *. 250kcmil Al in parallel if the guy is just looking for you to have more than 400A of conductor (which is not required).
Or
Parallel 3/0 Cu.
Saying 800kcmil is wild because that is technically still less than 400A. So I don't exactly understand his point. Unless you have a load or line side tapped power system that requires it to be larger than 360A but less than 400A.
You are allowed to use the round up rule in 240 as long as the conductor ampacity is larger than the load.
Or
Parallel 3/0 Cu.
Saying 800kcmil is wild because that is technically still less than 400A. So I don't exactly understand his point. Unless you have a load or line side tapped power system that requires it to be larger than 360A but less than 400A.
You are allowed to use the round up rule in 240 as long as the conductor ampacity is larger than the load.
Leonan
Member
- Location
- Massachusetts
- Occupation
- Electrician
I've never seen that either. I just wanted to make sure I'm covered by nec 310.12 because I used a 600 cmil aluminum
Leonan
Member
- Location
- Massachusetts
- Occupation
- Electrician
Leonan
Member
- Location
- Massachusetts
- Occupation
- Electrician
