arc flash at 208Y ?

[the blur]

any concerns with arc flash at 208Y?
we do alot of work in dusty enviorments on 600amp 208v service entrance panels.

 

[jumper]

I believe that 70E requires arc flash calculations are required on 208v systems fed by anything larger than a 112.5 kVA transformer.

That comes out to 312.5 amps, so you are past the limit at 600 amps.

 

[the blur]

ok, I have some more details; and I am totally new to arc flash. We have a 600a service and a 400a service coming off a pad mount transformer. The KVA rating of the transformer is worn off. But it's obviously designed around a 1000amps for both services coming into the building. It's a 208Y/120 and the primary side is most likely 7.2KV.

My position is senior plant mechanic/engineer. There's a lot of sub panels which I don't worry about.

My concern is the 600amp panel, which we go into once a year to vacuum the dust out, and look things over. We were a wood shop, and now we are a packaging plant. Still very dusty... The 600amp panel is about 50 feet from the pad mount, but is feed by parellel feeders. no doubt the fault current potential is there.

Do I need the full Nomex suit when going into the 600amp panel ? or is eye protection, and a good pair of gloves all that is necessary ?

 

[charlie b]

The amount and type of personnel protective clothing and equipment is a function of the amount of energy that can be released during an arc flash event. You can't know how much current that will be, without performing a calculation.

 

[jim dungar]

Do I need the full Nomex suit when going into the 600amp panel ? or is eye protection, and a good pair of gloves all that is necessary ?

It is extremely unlikely that the incident energy at your service entrance equipment is <40 cal/cm?. Also, because this is the service entrance location you probably do not meet the footnotes that would allow you to use the 'task table'.

 

[zog]

Should be done de-energized anyways.

 

[the blur]

Would you touch a 600a main breaker that has not been excerised in 25 years ?

In the practical world that we live in, what is practical to handle this task ?
meaning not shutting down an entire business, that runs a night shift, and weekend shifts, etc, etc.

 

[don_resqcapt19]

Would you touch a 600a main breaker that has not been excerised in 25 years ?

In the practical world that we live in, what is practical to handle this task ?
meaning not shutting down an entire business, that runs a night shift, and weekend shifts, etc, etc.

You need to schedule an outage. There is no provisions in the OSHA rules that would permit you to do what you want to do, no matter what PPE you use. Also that breaker should probably be tested to see if it still works.

 

[jumper]

Would you touch a 600a main breaker that has not been excerised in 25 years ?

In the practical world that we live in, what is practical to handle this task ?
meaning not shutting down an entire business, that runs a night shift, and weekend shifts, etc, etc.

It is not practical when someone is hurt or dies. OSHA will fine you big time, not to mention a personal lawsuit.

 

[the blur]

So shutting off the 600a main solves the entire problem, and I can work on the panel naked ?

not mentioning the 6 lugs (parellel feeds)on top of the main that are still hot, but behind a piece of card board.

 

[jumper]

So shutting off the 600a main solves the entire problem, and I can work on the panel naked ?

not mentioning the 6 lugs (parellel feeds)on top of the main that are still hot, but behind a piece of card board.

It you are looking for support on your position, you came to the wrong forum.

 

[the blur]

No, I am asking if shutting the main solves all the saftey aspect problems & requirements associated with arc flash.

 

[jumper]

If you mean the main in the 600 amp panel, then no. You have to de-energize the supply to it and verify.

 

[the blur]

And that requires a phone call to the poco to go inside the pad mount, and de-engerize from there.

 

[jumper]

And that requires a phone call to the poco to go inside the pad mount, and de-engerize from there.

As I am the junior grade grunt who has to clean the gear I can only say: Not my problem.

 

[tkb]

And that requires a phone call to the poco to go inside the pad mount, and de-engerize from there.

OSHA does not accept the excuse of "it was inconvenient" or "it is going to cost money" when there is an investigation into an accident.

 

[zog]

Would you touch a 600a main breaker that has not been excerised in 25 years ?

I woudl use a remote operator, but that is just me.

In the practical world that we live in, what is practical to handle this task ?
meaning not shutting down an entire business, that runs a night shift, and weekend shifts, etc, etc.

We do it every single day.

 

[zog]

Also that breaker should probably be tested to see if it still works.

NFPA 70E article 205.3 General Maintenance Requirements. Overcurrent protective devices shall be maintained in accordance with the manufacturers? instructions or industry consensus standards Maintenance, tests, and inspections shall be documented.

Informational Note: Refer to NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, and ANSI/NETA MTS-2007, Standard for Maintenance Testing Specifications for Electrical Power Distribution Equipment and Systems, for guidance on maintenance frequency, methods, and tests.