Are these panels undersized?

[Charles Holt]

This my first post, but I appreciate all that others have contributed. The home I was inspecting today has two service panels. The Challenger panel data plates say they are 150 amps maximum. The wiring to the panels is 4/0 aluminum. Seeing the larger wire size, I didn't think anything of it until I came to the main disconnects at the exterior of the home. The disconnects are 200 amps. Any help with this would be greatly appreciated as I haven't come across mismatched disconnects before.

 

[bob]

Do the Challenger panels have a 150 amp main breaker installed?

 

[infinity]

How long are the conductors between the disconnects and the panels?

 

[Charles Holt]

Do the Challenger panels have a 150 amp main breaker installed?

No main breakers at the panels. The 200 amp main breakers are at the meter.

 

[Dennis Alwon]

No main breakers at the panels. The 200 amp main breakers are at the meter.

I suspect someone screwed up if the panels are in fact 150 amp buss bars. Simple fix is to change the breakers outside to 150 as long as the load will warrant that, otherwise get some 200 amp panels. Unfortunately this would not help the situation unless the feeder is in conduit.

 

[Charles Holt]

How long are the conductors between the disconnects and the panels?

Approximately 50 feet

 

[Charles Holt]

I suspect someone screwed up if the panels are in fact 150 amp buss bars. Simple fix is to change the breakers outside to 150 as long as the load will warrant that, otherwise get some 200 amp panels. Unfortunately this would not help the situation unless the feeder is in conduit.

The home was built in 1997. The load is split between the two panels and I would suspect that installing 150 amp mains would pose not problems.

 

[ceb58]

The home was built in 1997. The load is split between the two panels and I would suspect that installing 150 amp mains would pose not problems.

In 1997 4/0 al SER would have been good for 200amp but someone screwed up with the 150's. Simplest fix is to change the mains to 150amp. Under 08 code 4/0 SER is good up to 150amp.

 

[infinity]

How long are the conductors between the disconnects and the panels?

Approximately 50 feet

Too bad. Although it's a poor choice, 10' or less and the 10' tap rule might apply.

 

[curt swartz]

Too bad. Although it's a poor choice, 10' or less and the 10' tap rule might apply.

You would still need 150 overcurrent protection for the panel.

I'm surprised that this house has Challenger equipment if it was built in 97. These panels must have been sitting in someones stock for at lease several years.

 

[infinity]

You would still need 150 overcurrent protection for the panel.

Would it if the calculated load was 150 amps or less?

 

[busman]

In 1997 4/0 al SER would have been good for 200amp but someone screwed up with the 150's. Simplest fix is to change the mains to 150amp. Under 08 code 4/0 SER is good up to 150amp.

We're still on 2005 here in VA, so I haven't bought the 2008 yet. Did they change the 315.15(b)(6) table in 2008?

Thanks,

Mark

 

[jumper]

We're still on 2005 here in VA, so I haven't bought the 2008 yet. Did they change the 315.15(b)(6) table in 2008?

Thanks,

Mark

No, they changed 338.10(B)(4). They deleted the exception to 334.80.

 

[busman]

No, they changed 338.10(B)(4). They deleted the exception to 334.80.

I guess I'm still missing something. The OP said it was a home, so why wouldn't you be able to use 310.15(b)(6)? How does that rule change under 2008?

Thanks,

Mark

 

[jumper]

I guess I'm still missing something. The OP said it was a home, so why wouldn't you be able to use 310.15(b)(6)? How does that rule change under 2008?

Thanks,

Mark

Here
is a current debate on the subject on the subject.

 

[Jim W in Tampa]

My best guess is this was accidently over looked by either installer , inspector or both.
150 amp breaker would been same price but maybe not in stock. You have a violation but very unlikely would ever cause a problem unless its loaded with some very large loads that might be on at same time. Easy to fix but not cheap.

 

[Jim W in Tampa]

This could turn into an interesting situation. Could the EC that installed this be forced to correct it being he created the violation. Warranty is one year but this is not really a warranty issue. If he sold this to be 400 amp service then what ?
Must say as a HI you were very alert.

 

[curt swartz]

Would it if the calculated load was 150 amps or less?

I'm assuming that these panels are lighting and appliance panels so they would require overcurrent protection at or less than their rating.

 

[infinity]

I'm assuming that these panels are lighting and appliance panels so they would require overcurrent protection at or less than their rating.

You're correct. I was thinking of a different application. In the 2008 NEC the lighting and appliance panelboard reference has been removed. The new applicable section would be 408.36.