400 amp main panel - line conductor size - code

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hardworker

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Is the following conductor the correct size for a 400 amp main panel to pass code? This is the line between the power company's meter and the panel. 10 ft. maximum run.

THHN500BK500 500MCM THHN STR Black

500-1C THHN/THWN2/MTW 600V Cu-37STR PVC Nyl-BLK 500RL WR
 
:)
hardworker said:
Is the following conductor the correct size for a 400 amp main panel to pass code? This is the line between the power company's meter and the panel. 10 ft. maximum run.

THHN500BK500 500MCM THHN STR Black

500-1C THHN/THWN2/MTW 600V Cu-37STR PVC Nyl-BLK 500RL WR
Click to expand...

This is a panelboard with a 400A main breaker installed correct? I assume since someone ordered a 400A panelboard they did the calcs and you are fine with the 500MCM.
 
Assumptions aside, it also depends on whether this is a 120/240 3-wire dwelling service or not. If it is, 400kcmil is permitted.
 
I did not do the installation, so I don't know what they did as far as calculations. It is a commercial building with a 400amp breaker. The panel has settings for sensitivity for 400amp breaker. It is set on the most sensitive setting.

It is a 120/240 3 wire.

A number of additional appliances have been added since the panel was installed. A/c window units, baseboard heaters, etc.

No problem with tripping of the breaker. It has never tripped.

Does it pass code as installed?
 
hardworker said:
Let me ask this question. With the conductors presently in service, is it safe to handle 400amps?
Click to expand...

As previously stated, the 500kcmil conductor is only good for 380 amps at 75 degrees to be NEC compliant. The wire itself is good for 430 amps at 90 degrees but chances are the terminals are only good for 75 degrees.

I dont think it will burst into flames immediately (or maybe never) with 400 amps but it would not be a code compliant install.

Pete
 
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