Is this allowed?

[rickjus]

Assume a Sq. D EZ meter pack with a 1,000AMP MCB connected to (6) 225AMP meter sockets each with separate 225A MCB feeding individual tenant spaces.

Does the code allow me to feed the 1,000AMP MCB section with (3) parallel runs of 4#350KCMIL (separate raceways) for a total conductor ampacity of 930 AMPS.

I think "NO" because 2002 NEC 240.4(C); 230.42; and 230.90(A) say you can’t.

However, if I replaced the 1,000AMP MCB with a wireway this could be achieved as there are a total of 6 main disconnects. Assuming the total load is less than 930 AMPS.

Comments?

 

[iwire]

I agree with your thoughts here.

Hows the power company want the metering? Line or load side of the service disconect(s)?

 

[rickjus]

I agree with your thoughts here.

Hows the power company want the metering? Line or load side of the service disconect(s)?

Does this really matter? There are (6) seperate meters. I would assume the (6) 225 AMP breakers are after meter (line side of the breakers) and all the meters are on the load side of the 1,000 AMP main.

 

[iwire]

Does this really matter?

That would be up to the local power company.

In my area many power companies want cold sequence (load side) metering on services above 150 to ground and hot sequence metering (line side) on services below 150 to ground.

Either way it is something you want to pin down before ordering the equipment.

 

[bphgravity]

I see this all the time. It's a simple manipulation of the code that some design professionals take advantage of. If it wasn't for the fact that Article 220 and 310.16 are so conservative, I might be more worried...

The change in arrangment could significantly effect SCCR and AIC ratings...

 

[rickjus]

My interpretation of this is either the wire is too small...or...the 1,000 AMP main would need to be converted into an MLO section of the EZ-Meter pack. I just don't see how this would be code complient...

Coments?

 

[iwire]

My interpretation of this is either the wire is too small...or...the 1,000 AMP main would need to be converted into an MLO section of the EZ-Meter pack.

It's been a while since I have worked on meter stacks but I would want to make sure that the meter stack without a main is still UL listed as service equipment.

If the meter stack can keep its service rating without a main than the NEC would allow this installation per 230.90(A) Ex 3.

I would be surprised if the meter stacks are service rated without a main on the supply side.

While I see many MLO panels used this way I have never seen a MLO meter stack used this way.

 

[Smart $]

...

Does the code allow me to feed the 1,000AMP MCB section with (3) parallel runs of 4#350KCMIL (separate raceways) for a total conductor ampacity of 930 AMPS.

I think "NO" because 2002 NEC 240.4(C); 230.42; and 230.90(A) say you can?t.

...

Is 400kcmil no longer available?

 

[rickjus]

Okay, let me rephrase the question.

Assume I have an exterior service containing a wireway feeding (6) separate 200 AMP feed-thru meters with 200 AMP fused disconnects feeding individual tenant spaces, all are grouped.

The conductors are (3) separate parallel runs of 4#350KCMIL Cu (930 AMPs) from the utility transformer to the wireway. The individual meters are tapped from these conductors to feed the tenant panels. 2002 NEC 230.90(A) exception 3 allows me to do this?.Right?

Now, if I replace the wireway with a 1,000 MCB do I still comply? Given 2002 NEC 240.4(C); 230.42; and 230.90(A)?