need advice,head scraching

Status
Not open for further replies.
M

mdh

Member
I was at a industrial plant today that has been idol for twenty-five years for as in operation,has been used as storage and minor equiptment. It has 480v 3-phase wey service with transformers 480 y to 208 y for 120 and 208 loads,here is my question at the main pnl has A B C and N into main bkr pnl which is ok,there is another pnl conected next to this pnl that is a main lug only with (six bkrs only) and they are fed with A B C service conductors with no N conductor,would the 6 handle rule apply here without a main? they feed motor loads only.BTW these pnl's are about 30 feet inside the buildingThere are another set of A B C service conductors going to a 400 amp fused disconect then to the cap bank for power factor corection.

Does this sound right?
 
Is there a breaker in the "main" panel that feeds the panel you question ?
 
Huh?

Huh?

mdh said:
I was at a industrial plant today that has been idol for twenty-five years for as in operation,has been used as storage and minor equiptment. It has 480v 3-phase wey service with transformers 480 y to 208 y for 120 and 208 loads,here is my question at the main pnl has A B C and N into main bkr pnl which is ok,there is another pnl conected next to this pnl that is a main lug only with (six bkrs only) and they are fed with A B C service conductors with no N conductor,would the 6 handle rule apply here without a main? they feed motor loads only.BTW these pnl's are about 30 feet inside the buildingThere are another set of A B C service conductors going to a 400 amp fused disconect then to the cap bank for power factor corection.

Does this sound right?
Click to expand...

I would like to help, or at least understand, but between the abreviations, odd spellings and terminology, I do not understand what you are trying to get to. For example you talk about "A B C and N into main bkr pnl" then "main lug only with (six bkrs only) and they are fed with A B C service conductors " fed from where, a tap on the service conductors, or are they in fact not "Service conductors" Perhaps a sketch of the distribution would help. Otherwise, the 6 handle rule is not really difficult. If all the power from the utility can not be turned off with 6 handles, everything dead, no 120, no 208, no 480 then it is not legal.
 
OK hope i might explain better,The service is a 480 Y service into the building, goes inside to panel #1 400 amp with main breaker fed with 500mcm with nuetral conductor bonded inside that panel that looks fine.

another panel next to this that does not have a main breaker,fed with 500 mcm goes to outside to service drop,without a neutral conductor,no disconect has six breakers in it.,just thought if it was wey service the neutral had to be ran in even if it was not needed on motor loads that have no neutral curents.
 
From what you describe you have more than 6 service disconnects - that is a problem.

The panel with 6 breakers - if a service must have grounded service conductor installed even if there is no neutral load. That is another problem.

If the panel with 6 breakers is not a service panel then it does not require a grounded (neutral) conductor, but does require an equipment grounding conductor. The six breaker rule does not apply to this if it is not service equipment, or the main disconnect (s)of a building supplied by a feeder.
 
mdh said:
OK hope i might explain better,The service is a 480 Y service into the building, goes inside to panel #1 400 amp with main breaker fed with 500mcm with nuetral conductor bonded inside that panel that looks fine.

another panel next to this that does not have a main breaker,fed with 500 mcm goes to outside to service drop,without a neutral conductor,no disconect has six breakers in it.,just thought if it was wey service the neutral had to be ran in even if it was not needed on motor loads that have no neutral curents.
Click to expand...

First, the 6 handle rule is violated in this installation. The second panel would need an MCB, or a disconnect.

Second, as far as I know, the neutral does not need to be run just because the feed transformer is a Wye configuration.
 
Strathead said:
Second, as far as I know, the neutral does not need to be run just because the feed transformer is a Wye configuration.
Click to expand...
What is going to clear a fault? See 250.24(C)

Roger
 
Last edited:
Strathead said:
First, the 6 handle rule is violated in this installation. The second panel would need an MCB, or a disconnect.
Click to expand...

I don't see this as being a violation of the 6 handle rule, as two different sets of service entrance conductors is described. 230.71 says that the disconnecting means for EACH service or EACH set of service conductors shall consist of not more than 6 switches or circuit breakers.

(Whether or not the two sets of service entrance conductors is permitted by 230.2 or 230.40 is another matter.)
 
david luchini said:
I don't see this as being a violation of the 6 handle rule, as two different sets of service entrance conductors is described. 230.71 says that the disconnecting means for EACH service or EACH set of service conductors shall consist of not more than 6 switches or circuit breakers.

(Whether or not the two sets of service entrance conductors is permitted by 230.2 or 230.40 is another matter.)
Click to expand...

I thought you would be wrong somehow, but after looking at your reference, I stand corrected and a little surprised.
 
Strathead said:
250.20 (B)(2) The neitral is not being used as a circuit conductor.
Click to expand...
Which has nothing to do with the reason for the requirement of 250.24(C). Once again, what do you think will clear a fault at the service? The OP has already said the service is a grounded wye.

Roger
 
Last edited:
Status
Not open for further replies.
Top