# Hi-leg where to land



## chenley (Feb 20, 2007)

It's the same with my Poco here, the meter can itself even has a label on it to land the stinger on the C phase. I'll land it on the C phase in the meter can and put it on the B phase at the first disconnect.


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## BuzzKill (Oct 27, 2008)

can't touch that around here, the poco side. B phase after.


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## slickvic277 (Feb 5, 2009)

I wonder why this so common?The utility were I'm at does the same thing.
Anyone familiar with knowledge of the poco's line of thought care to chime in?Do they acknowledge the NEC at all?


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## GoodLookingUglyGuy (Feb 3, 2010)

poco I assume is pud public utility dept. isn't the metering can the building owners equipment. anything located off the building I can see belonging to pud. as I am responsible for all maint/install repair until the pud point of connection and even lets say a lug burns up in the mdp thats still the building owners bill


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## NolaTigaBait (Oct 19, 2008)

BuzzKill said:


> can't touch that around here, the poco side. B phase after.


Same here. I don't think the nec can trump them. They have their own set of standards they abide by.


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## GoodLookingUglyGuy (Feb 3, 2010)

slickvick I understand the pud has their own codes but when it hits the building I would think that its nec what poco stand for


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## slickvic277 (Feb 5, 2009)

NolaTigaBait said:


> Same here. I don't think the nec can trump them. They have their own set of standards they abide by.


I understand that,but you would think there would be a working understanding of the NEC and there own rules.I'm just curious about the technical reasoning behind making the high leg the "c" phase,being it effects the rules in witch our installations must abide.And the safety of the customers equipment.


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## wayni (Aug 27, 2007)

slickvic277 said:


> I understand that,but you would think there would be a working understanding of the NEC and there own rules.I'm just curious about the technical reasoning behind making the high leg the "c" phase,being it effects the rules in witch our installations must abide.And the safety of the customers equipment.


Same thing happens here. Poco comes in on C phase, it is up to us to reroute to B before the first disconnect. 

The NEC itself states that it does not apply to the poco, save for office buildings and the like not associated in generation, distribution and transmission of electricity. This is in NEC 90.2 A and B.

As for the reasons - There must be some technical answer, yes. I think it has to do with that's how they've always done it and changing the game at this point would cause them more safety issues than it does us.


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## micromind (Aug 11, 2007)

If it's a self-contained feed-through meter, the high leg must be on C phase. It's the way the meter is built, and cannot be changed. 

If it's a CT installation, the high leg can be any phase. Most POCOs require it to be C, because all of their other high legs are on C. Remember, a lot of linemen aren't exactly....well.....

This makes for an interesting scenario when the main breaker is bussed. A lot of boards, you can swap A and C, but not B. 

Even if you show them the NEC, they'll just laugh; 'Code doesn't apply to us'. 

This doesn't help at the switchgear, but I've landed the feeders Blue, Black, Orange on the breakers, then Black, Orange, Blue at the panels. The rotation is the same, the panels are compliant, but the switchgear is not. 

This is another one of those things where the electrician is caught between a rock and a hard spot. There's no way to win.

Rob


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## RePhase277 (Feb 5, 2008)

One of the old code gurus here can probably look it up, but didn't the NEC used to require the high leg to be C phase back in the 70s? If so, the question is, why did the NEC change?


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## codeone (Sep 15, 2008)

slickvic277 said:


> I wonder why this so common?The utility were I'm at does the same thing.
> Anyone familiar with knowledge of the poco's line of thought care to chime in?Do they acknowledge the NEC at all?


 THE POCO uses the NESC ---- National Electrical Safety Code. Its quite different from the NEC. I have an old copy somewhere If I can find it Ill look it up.


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## BuzzKill (Oct 27, 2008)

codeone said:


> THE POCO uses the NESC ---- National Electrical Safety Code. Its quite different from the NEC. I have an old copy somewhere If I can find it Ill look it up.


 yeah it's quite different than the NEC..I'd like to get a copy of one of those out of curiousity.


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## John Valdes (May 17, 2007)

InPhase277 said:


> One of the old code gurus here can probably look it up, but didn't the NEC used to require the high leg to be C phase back in the 70s? If so, the question is, why did the NEC change?


Yes, back in my early apprenticeship years it was on "C" phase. It is the only high leg system I ever have worked on in 35 years in the trade. I know how the high leg is derived from the delta xfmr, but have always wondered why anyone would ever use the high leg for a service panel or feeder. Isn't the high leg phase useless for 120 volt loads? How does one land a high leg on a panel buss and be certain someone does not smoke a computer? Why would anyone bring a 3 phase delta high leg service to any panel? If the panel where all three phase loads I can see it, but for 120/240 loads?  I sure would like an explanation regarding this high/wild leg system. Not how you get a high leg, but how do you deal with a phase of higher voltage in the same panel.


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## RePhase277 (Feb 5, 2008)

John Valdes said:


> Yes, back in my early apprenticeship years it was on "C" phase. It is the only high leg system I ever have worked on in 35 years in the trade. I know how the high leg is derived from the delta xfmr, but have always wondered why anyone would ever use the high leg for a service panel or feeder. Isn't the high leg phase useless for 120 volt loads? How does one land a high leg on a panel buss and be certain someone does not smoke a computer? Why would anyone bring a 3 phase delta high leg service to any panel? If the panel where all three phase loads I can see it, but for 120/240 loads?  I sure would like an explanation regarding this high/wild leg system. Not how you get a high leg, but how do you deal with a phase of higher voltage in the same panel.


You just skip every third breaker space. That is always a good sign that you have a high leg panel. And labeling is a must. You can't prevent stupidity, plain and simple. I always check the voltages in every panel I work in just in case.

The system is used when you have 240 V three phase loads. But at the same time you always have 120 V loads like lighting and office equipment. Besides that you have to ground the system, and the result is two perfectly usable 120 V legs, why not use them?


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## Noe (Apr 7, 2009)

I know this is an out dated thread, but we just covered this in class the other night. The reason Utility requires Hi leg on C is that meters require 120V to operate which they draw off of A and B Phase. Easier for them to change our wiring then to change the meter design.


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## Nephi (Mar 20, 2010)

i have been on a number of service calls where a maintenance man or equivelent had smoked a lighting load, computer , pop machine microwave etc. wild leg deltas are not the problem but the marking of them. i go out of my way to make it painfully obvious that c phase is high. I have never put the high leg on any phase other than c and mark it orange


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## WIREDOG (May 27, 2007)

the most common i have seen is in warehouses and lease spaces. this system is not what you would consider a normal delta system because it is specific for this use. the beast is a 120/208 with a 277 hi- leg. hi leg is used for lighting only and it allows customer to keep from installing a seperate panel for one or two lighting circuits. as far as the placement of the hi-leg. if poco asks for the hi-leg to be on "c" phase let them have it and change it in the gear as needed. the only thing that changes is the rotation, the meter socket could care less if what voltage it is. use more orange tape if you cant seem to manange smoking equiptment.


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## Nephi (Mar 20, 2010)

meter channels do care what phase the wild leg is on seeing how most meters pic up a and b . its just good practice to keep the wild leg consistent through out the building and clearly marked. the excessive marking isnt for me but for diyers who could potentialy come in contact with 277


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