Can a 999A trip setting avoid ground fault protection requirement?

[vavelar]

I'm hoping someone can answer the following. The link below says that I can meet NEC 240-6(c) by sealing the trip unit.

http://www.schneider-electric.us/si...&country=US&lang=EN&id=FA120964&redirect=true

"Yes, the 400A DJM circuit breaker has an adjustable AMPERE RATING feature allowing the trip settings to be dialed down from 400A maximum to 160A minimum. A Tamper-evident seal kit is also available for this DJM circuit breaker by ordering catalog number: 29375. This seal kit meets NEC 240-6(c) requirements. Refer to PAGE 12 & 13 of the following document for details on how to dial-down the ampere rating of this DJM circuit breaker.
http://ecatalog.squared.com/pubs/Circuit%20Protection/Molded%20Case%20Circuit%20Breakers/Merlin%20Gerin%20Molded%20Case%20Circuit%20Breakers/06"

However, can I avoid using GFP under 230.95 by using this method?


230.95 Ground-Fault Protection of Equipment.
Ground-fault protection of equipment shall be provided for solidly grounded wye electric services of more than 150 volts to ground but not exceeding 600 volts phase-to-phase for each service disconnect rated 1000 amperes or more. The grounded conductor for the solidly grounded wye system shall be connected directly to ground through a grounding electrode system, as specified in*250.50, without inserting any resistor or impedance device.

The rating of the service disconnect shall be considered to be the rating of the largest fuse that can be installed or the highest continuous current trip setting for which the actual overcurrent device installed in a circuit breaker is rated or can be adjusted.

 

[jim dungar]

However, can I avoid using GFP under 230.95 by using this method?

IMHO - No.

Notice how the last sentences uses the phrase 'can be adjusted' and also mentions the largest possible fuse.
230.95 is not dependent on 240.6.

Why are you trying so hard to avoid GFP?

 

[hurk27]

Why is the OP even worrying about GFP if the breaker is only a 400 amp? its only for 1K Amps or more with a voltage of 150 volts to ground or more?

If the service is 1K Amps or more then GFP will be required, this is what the service is rated at not what the breaker is rated at, and if so I would never avoid using a GFP, because if you have a grounding path that ever fails violently and someone were to be hurt of killed the liability could be very costly! an arc flast blast could happen anywhere in the ground path and if someone just happened to be near it when it happened well the rest I think you know.

Were talking about service that can have many thousands of amps in a bolted ground fault.

 

[don_resqcapt19]

...
Were talking about service that can have many thousands of amps in a bolted ground fault.

This code section is not aimed at a bolted ground fault. The standard breaker will open under bolted fault conditions. It is aimed at an arcing ground fault where the impedance of the arc limits the current to a level that is below the instantaneous or very short time trip points.

 

[steve66]

I agree with Jim.

(I also agree with Hurk, but after reading the post again, I think the 400 amp breaker is just an example. The question seems to be can the same logic be applied to a 1000 amp breaker that is set slightly lower.)

The link says the adjustment may be used to comply with 240.6(C). It doesn't say anything about 230.95. And 230.95 specifically says it is based on the frame size, or highest continuous trip setting.

So no, you would still need GFP.

If you really want to avoid using GFP, divide your loads into two groups, and use 2 separate smaller services or feeders.

 

[templdl]

In all seriousness does the OP really considering doing this or this just a point for discussion? Could it be classified as "you have to be kidding". What I do know is that if you are a fisherman there are lake the have a 10hp limit for outboard motors. As such there are 9.9hp motors. Could it be that 999a frame breakers are next?

 

[jap]

I would say if a 480v breaker was capable of being dialed up to 1000 amps, then the GFI rule would still be
in affect.

Otherwise the rule stands at 1000 amps and above whether you like it or not.

Therefore if the Max overcurrent protection is below 1000 amps 480v, even if by just 1 amp,I dont see how you could enforce the GFI rule for 1000 amps and above.