High leg question

[Awg-Dawg]

I see this on alot of equipment we hook up......

Warning! Connect High leg on center pole,L2,etc.

The equip. is 3 phase 3 wire.


Wouldn't it function the same with the high leg on any pole?

 

[480sparky]

See 408.3(E) and 409.102(B)

 

[Awg-Dawg]

See 408.3(E) and 409.102(B)

Yeah, I got that.

It was more of a theory question.:smile:

 

[augie47]

hi-leg

hi-leg

if it's 3 phase 3 wire, it would work the same, no matter

 

[kbsparky]

....Wouldn't it function the same with the high leg on any pole?

IF the equipment has a neutral connection for control wiring, etc, then the high leg might be damaging to the equipment.

BUT, if there is no grounded circuit conductor present, in theory it really doesn't matter where the high leg is connected.

The high leg is normally connected to the "B" phase, and you are limited by 110.3 to follow any manufacturer's instructions anyways...... :roll:

 

[LarryFine]

Wouldn't it function the same with the high leg on any pole?

Yes, it would. I believe it's just a physical thing; a way to keep the high leg just a bit farther from fingers.

 

[sparky_magoo]

The last shop I worked for always landed the high leg on the third pole. I thought it was wrong.

I always knew the stinger landed on the middle pole. I am very greatful to now be working for a guy who wants everything done right.

 

[eric stromberg]

My question, concerning all this discussion of the "High Leg," is, why does the Code allow this type of installation at all? It seems to me that the three phases would go into a gutter, there would be a 240/120 panel for single phase loads, and the three phase loads would be in individual disconnects hanging off of the gutter. There must not be enough of a documented body count to get the Code to disallow this. This is one change i'd like to see in the 2011 Code.

 

[jim dungar]

My question, concerning all this discussion of the "High Leg," is, why does the Code allow this type of installation at all? It seems to me that the three phases would go into a gutter, there would be a 240/120 panel for single phase loads, and the three phase loads would be in individual disconnects hanging off of the gutter. There must not be enough of a documented body count to get the Code to disallow this. This is one change i'd like to see in the 2011 Code.

This system has been in use for more than 70yrs.

If I was desiging a machine that need a small amount of L-N voltage I would not to have to run two seperate circuits to it.

 

[eric stromberg]

This system has been in use for more than 70yrs.

If I was desiging a machine that need a small amount of L-N voltage I would not to have to run two seperate circuits to it.

Excellent point. I hadn't thought of that. The machine could also have a control transformer in it that would provide the necessary voltage.

 

[Minuteman]

I see this on alot of equipment we hook up......

Warning! Connect High leg on center pole,L2,etc.

The equip. is 3 phase 3 wire.


Wouldn't it function the same with the high leg on any pole?

If the equipment uses "A" and/or "C" for some single phase loads, it would matter where the Wild Leg was landed.

 

[mdshunk]

If the equipment uses "A" and/or "C" for some single phase loads, it would matter where the Wild Leg was landed.

What makes you think that? :-?

 

[Minuteman]

If the equipment has some 120v courtesy outlet, or 120v lamps, or motor, or whatever, then the factory would connect that load to A or C and neutral - right? However, if the Wild Leg lands on C and it has some 120v loads in the equipment...

 

[mdshunk]

If the equipment has some 120v courtesy outlet, or 120v lamps, or motor, or whatever, then the factory would connect that load to A or C and neutral - right? However, if the Wild Leg lands on C and it has some 120v loads in the equipment...

Save for the fact that the OP said it was straight 3-phase, with no neutral. I thought you were talking about a 240 volt load, connected A to C. Guess not.

 

[Minuteman]

The equip. is 3 phase 3 wire.

Sorry, missed the 3 wire part. My bad.

 

[Karl H]

my understanding why the "High-Leg" was required to be on the "B" phase.Was so that any point that you measured voltage on the pnl you had to read 240 AB 240BC 120A to N 208B to N 120 C to N plus of course the Orange Marking.

 

[frenchelectrican]

Karl H:;

Yeah but unforetally there is some delta system have diffrent marking i know the old delta system they did marked in red marking for delta but normally it will be marked in orange which this is current marking for delta system is

Merci , Marc

 

[mikehughes8]

I think the high-leg should be marked with yellow or something.....i dont like orange

thats my addition to the 2011 NEC....wish me luck

 

[hardworkingstiff]

I think the high-leg should be marked with yellow or something.....i dont like orange

thats my addition to the 2011 NEC....wish me luck

LOL, good luck!

 

[brian john]

High legs have been in use for years and other that the regularly damaged 120 VAC equipment improperly connected to the "High Leg", this system was successfully used. In our area the high leg is going the way of 2-phase 5-wire, so NEC changes regarding high legs is really becoming a non-issue around here.