# Bit Confused



## DPDT (Nov 3, 2007)

Bare with me here folks...

Xformer pad, OP meter, and general service meter combo is 125' from the house. Two runs of 4/O URD from meters to two 200A panels in the house. The OP panel has a 25KW boiler and a 5KW water heater on it giving it a load of approximately 125 amp. Now the inspector didn't fail us on this one but stated we now have to run 250 to our OP 200 amp panels from now on. I wasn't involved in the conversation so I have no code reference to this. How should I be sizing the OP feeder?


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## bigredc222 (Oct 23, 2007)

He only 250 to the OP panel not the regular one. 4/0 is what we've all been using for 200 A panels forever. They don't offer OP around here anymore. I still have it. I can't think of why. Maybe for distance, at that job. But why wouldn't you do both. Maybe with that much load when it kicks on it will pull a lot of amps all at once and cause a voltage drop. But that would be just that job again. I'm curios. That's all I can up with.


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## gilbequick (Oct 6, 2007)

I give, what's an "OP meter"?


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## Magnettica (Jan 23, 2007)

That's what I was thinking... what the hell's an OP meter/ panel?


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## DPDT (Nov 3, 2007)

Sorry guys. OP=Off Peak panel. With a radio box we use a Load Management Control (LMC) set of contacts (dry) to the loads. Our other POCO in this area uses a collared meter where the meter is remotely de-energized killing the OP Panel panel during peak hours.


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## DPDT (Nov 3, 2007)

Sooooo...I have two (are they feeders or SEC's <Fed from 200A Outdoor Disco/Panel Combos> and does it matter for sizing?) runs of 4/O. Are you confused yet? I am. Boss says continuous load and if it was a branch circuit, I would agree with 125% sizing of continuous load on branch circuit load but I think I could size the feeder to the OP panel by 310.15b, right? Man, I need some sleep....


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## bigredc222 (Oct 23, 2007)

DPDT said:


> Sooooo...I have two (are they feeders or SEC's <Fed from 200A Outdoor Disco/Panel Combos> and does it matter for sizing?) runs of 4/O. Are you confused yet? I am. Boss says continuous load and if it was a branch circuit, I would agree with 125% sizing of continuous load on branch circuit load but I think I could size the feeder to the OP panel by 310.15b, right? Man, I need some sleep....


 talk to your boss and get more info


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## bigredc222 (Oct 23, 2007)

The confusing part for me is the inspector saying use 250 from now on for all of your OP panels. If that's the case then none of the particulars of this job come into play.


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## 480sparky (Sep 20, 2007)

gilbequick said:


> I give, what's an "OP meter"?





Magnettica said:


> That's what I was thinking... what the hell's an OP meter/ panel?


http://www.acronymfinder.com/


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## DPDT (Nov 3, 2007)

Figured it out. SECs or Feeders sized by 310.15b6 Table are when the main power service or feeder is feeding the appliance/lighting circuit panelboard. The OP panel would be considered a power panelboard therefor sized via 310.16. The wording is a bit odd but...it's the code.


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