1000a +

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augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
(short answer) No :grin:

Only disconnects 1000 amp or more and systems > 150 volts to ground require GFP, so a 1k amp MLO service panel with 400 amp beakers would not need GFP nor would a 208Y/120 service.
In addition, there are exceptions to the rule.
 
In agreement....my problem

In agreement....my problem

I agree with 230.95. I have a problem with a GFP 1600amp 277/480v service that keeps tripping the GFP main when an air conditioning compressor fails. In the past it tripped when a maintenance man was changing a light bulb and shorted wires together. I am told that they have adjusted the setting of the GFP breaker to it's maximum allowed setting. Any advice on correcting this problem?
thank you,
:confused:
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
I agree with 230.95. I have a problem with a GFP 1600amp 277/480v service that keeps tripping the GFP main when an air conditioning compressor fails. In the past it tripped when a maintenance man was changing a light bulb and shorted wires together. I am told that they have adjusted the setting of the GFP breaker to it's maximum allowed setting. Any advice on correcting this problem?
thank you,
:confused:

Zog or Brian John on here would be the guys to ask.

I imagine you'll need a coordination study done by a reputable outfit. Simply turning the dial up isn't the right way to go about it.
 

iwire

Moderator
Staff member
Location
Massachusetts
I have a problem with a GFP 1600amp 277/480v service that keeps tripping the GFP main when an air conditioning compressor fails. In the past it tripped when a maintenance man was changing a light bulb and shorted wires together.

That is odd, as a light bulb is usually 120 volt and the 480 volt main GFP would never see a ground fault on 208 or 120 volt circuits.
 

kwired

Electron manager
Location
NE Nebraska
That is odd, as a light bulb is usually 120 volt and the 480 volt main GFP would never see a ground fault on 208 or 120 volt circuits.

maybe it was a 277 volt luminaire. Or even 480 volt. Maintenance man may have been doing more than just changing a lamp - especially if he already tried that and it still did not work.
 

iwire

Moderator
Staff member
Location
Massachusetts
maybe it was a 277 volt luminaire. Or even 480 volt. Maintenance man may have been doing more than just changing a lamp - especially if he already tried that and it still did not work.


All I am saying is it is odd, I am aware of the possibilities.
 
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