6 service switch rule and arc flash

[cvirgil467]

anyone know if using the six service rule compromises arc flash protection?

thanks
c

 

[iwire]

I do not understand your question.

 

[Pierre C Belarge]

I see you are a consultant.

There is a myriad of information available on the net in regards to Arc Flash. Maybe you should study some and then come back with some questions.

 

[cvirgil467]

I shoud have been more specific.

Does the hazard risk increase when using the six switch service rule in lieu of a main circuit breaker?

 

[Dennis Alwon]

I shoud have been more specific.

Does the hazard risk increase when using the six switch service rule in lieu of a main circuit breaker?

What hazard are you referring to.

 

[billsnuff]

If there is no OCP between the xfmr and the disco, either one or six, the IE or HRC should be the same for each and that would require a calculation to determine the level of hazard.

hey ZOG.........it's for you....

 

[jim dungar]

Arc flash energy can only be reduced by having an OCPD open and extinguish the arc. Any panel/switchboard/disconnect that is connected to the utility, as a "main" device, should be considered as having more than 40 cal/cm­?. Many of my customers will not allow fuses to be changed in six service rule equipment except when a power outage has been taken.

 

[hardworkingstiff]

Many of my customers will not allow fuses to be changed in six service rule equipment except when a power outage has been taken.

Jim,

Will you explain this a little more? I don't understand. Are you saying the PoCo must kill the transformer to change one set of fuses even though opening the knife blades removes power from the fuse holder?

 

[zog]

If there is no OCP between the xfmr and the disco, either one or six, the IE or HRC should be the same for each and that would require a calculation to determine the level of hazard.

hey ZOG.........it's for you....

I dont understand the question, I dont think the OP understands what they are asking.

 

[jim dungar]

Jim,

Will you explain this a little more? I don't understand. Are you saying the PoCo must kill the transformer to change one set of fuses even though opening the knife blades removes power from the fuse holder?

Yes.

Opening the knife blades does not remove the arc flash potential from the line side of the switch.

Although some of these customers will allow "service" fuses to be removed, from energized panels, if the switch contains built-in fuse pullers.

 

[ron]

Since the question is nebulous, I'll respond with ....
Sometimes multiple smaller service switches (in lieu of one large) reduce downstream arc flash incident energy as the smaller upstream OCPD will generally open quicker and reduce incident energy to the downstream circuits.