240 volt 3 phase delta

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dmplec

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Have you ever had a power company want a single phase meter base for a 3 phase delta 240 volt service with one leg not metered
 
Answer to the original post. YES. This was old industrial facility that had two services. One delta 3 phase 3 wire 240 VAC one single phase 240/120 VAC
 
dmplec said:
Have you ever had a power company want a single phase meter base for a 3 phase delta 240 volt service with one leg not metered
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If this is 240V 3W delta and not 240/120 4W, then you do not need to meter all of the legs. Blondel's Theorem is at work. The third leg must equal the sum of the other two legs.
 
your right but finding a single phase meter base with a ul sticker that is approved for 3 phase or considering it single phase and allowing a splice in the meter will be difficult. seems like there is a better way to make everyone happy and make a safe install
 
dmplec said:
allowing a splice in the meter will be difficult.
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What splice?

It sounds like your getting a corner grounded service and that third phase which is grounded will land on the neutral bar of the single phase meter socket.

If I am right that it is corner grounded, that the grounded conductor will have to be marked white.


So a circuit to a 3 phase motor would have one white phase and two not white phases.
 
iwire said:
If I am right that it is corner grounded, that the grounded conductor will have to be marked white.
So a circuit to a 3 phase motor would have one white phase and two not white phases.
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While we both know that is the code rule, have you actually seen that in the field? I have never seen a white used on this system as required by the code.
 
don_resqcapt19 said:
While we both know that is the code rule, have you actually seen that in the field? I have never seen a white used on this system as required by the code.
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I agree, all of the 240 volt corner ground delta systems that I have seen did not, in fact have the grounded conductor phased white.

Chris
 
raider1 said:
I agree, all of the 240 volt corner ground delta systems that I have seen did not, in fact have the grounded conductor phased white.

Chris
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The one that I have worked on in the past did have B phase colored white.
 
don_resqcapt19 said:
While we both know that is the code rule, have you actually seen that in the field? I have never seen a white used on this system as required by the code.
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No, and I will also add I bet I can count on one hand the number of times I have seen corner grounded delta.

Wye services are the norm here.
 
the service is not a corner grounded delta. it is a straight 240 volt 3 wire 3 phase delta service to run (2) 240 volt 3 phase machines and that is it.
 
dmplec said:
the service is not a corner grounded delta. it is a straight 240 volt 3 wire 3 phase delta service to run (2) 240 volt 3 phase machines and that is it.
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OK, and come back w/ the pictures of Main & Service Point. ...:roll:
 
I just had a look at the service going into a space we are about to rent.

240V corner grounded delta. The B phase is candy-striped red and white, and grounded at the service. I suspect that this is the only grounding on the system; no apparent grounding at the transformer bank.

-Jon
 
charlie said:
You never have to meter all the legs, you need one less element (CT) than you have phases. Thanks Jim :)
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With the restriction that the leg with the missing element is used as the common point for the voltage coils.

[PS: and it is one less element than you have circuit conductors, including the neutral]
 
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I just came home from a job and came across the same situation, a 230V Delta system with a single phase meter base. In my 20 years, I've never seen this, so I was pleasantly surprised to see this post was only a week old.

One question about this system, I checked the voltage, phase to ground, on the leg which passed straight though and got 516V. Does this sound right? I did measure 230V phase-phase. I did not, for some reason, check the other two phases to ground.

My biggest issue is that I need to replace the main disconnect with a panel and have a hot leg with 500+ volts on it that does not go off when I pull the meter!
 
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