Older panel and problem

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EDC

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Hello,

First post here...

I know little about wiring but learn quickly. I'm starting a glass blowing shop and recently am renting a new building with a 200amp service. The service is apparently a slightly out of date service and I think the breakers are off or something.

All my 120 saws, grinders etc.. work fine but I think my voltage is off. I recently acquired a multi meter and I get wierd readings. All of the supposedly 110/120 recepticals are reading about 180 (though my appliances seem to work fine). My supposed 220/240 lines are reading wierd as well.

The panel I have has every 3rd space empty... and I think this has something to do with the odd power.

Maybe someone can shed some light on my issue?

Thanks,
Donovan
 
Re: Older panel and problem

You have not indicated on which terminals you made the measurements. How many conductors are coming in from the utility? Is it 240/120 volts, single-phase or a three phase system?
John
 
Re: Older panel and problem

Not sure why you're getting the crazy voltage readings but if every 3rd breaker is not used I would guess that you have a 120/240 volt, 3 phase, 4 wire Delta system where the missing breakers are on the high leg phase.
 
Re: Older panel and problem

I note that your profile states that you are a glass blower. You also stated that you know little about wiring so the best advice that any one here or elsewhere could give you is to seek the advice of a professional.
I dabbled a little with heating glass a few years back but if I was looking to get a nice piece of blown glass I would come see you instead of asking how to do it myself. What you do takes years of experience to learn just as the art of electricity.
There is a safety issue that needs to be considered when you start trying to repair this problem yourself therefore let me say again, please call an electrician.
:)
 
Re: Older panel and problem

Good advice above!

Just to make sure it isn't the multimeter, take it to another building and make sure it will read the outlets there correctly. I cannot think of an incorrect way the building could be wired that would mess up both the 120 and the 240

Ask whomever you get to check for problems on the neutral.

The reason for the missing every 3rd breakers is probably to miss the high voltage lugs of a center-tapped 3 phase delta electrical service (120/240 3 phase 4 wire). You could possibly have some 120V circuits connected to that 180-210V high voltage leg instead of the other two which are 120V when measured to the neutral or ground in the receptacle.

I would stop using anything I valued much on any outlet I measured over 130V at, BUT....... if it is a problem with the neutral, the voltages the tools get depends on what is connected and turned on at the time...........It could be bad

Get an electrician now.

Jim

[ June 04, 2005, 01:00 AM: Message edited by: ccjersey ]
 
Re: Older panel and problem

Thanks for input.. I believe Infinity is right on. For JW.. The electrician was here last week. He will be doing my new circuits... In fact, it was because of him that the light bulb went off that something was wrong. He didn't measure any voltage while he was here so he didn't catch the problem... He *did* mention to me however, that I should be careful in adding any breakers because it could cause things to "get off" (paraphrasing). He then went on saying something about a phase angle and 180V...

It then took me about 4 or 5 days to finally realize (on a Saturday) that I was probably using the multimeter right all along and that my duplex recepticles *were* actually getting 180V.

Anyway, to furthur respond to JW's lecture. I am a person who likes to learn. Yes, when it comes to my business, I will hire a pro... but that doesn't mean I can't learn about things. I find that these forums can be a wealth of information.. and I was happy to see all the responses from this forum when I got back to my computer.

Ultimately, the electrician will probably fix all of this but, for academics sake...

I have a meter/service going into one building. The building has two shops within it. The two shops each have their own sub-panel. My subpanel is the first one in the heirarchal order. I've looked at my breakers and they appear to be right.
ie... Every "b" space is empty. My questions is this:

If the breakers are messed up on the other shops panel (down stream)... can that cause the problem of all my duplex recepticals to get 180V?? In other words, from what I gathered from my meeting with the electrician, a mis-placed breaker can mess up other circuits in this kind of system.

Can someone comment?

Lastly, I also gathered from this electrician that power companies don't like this kind of service and that, much of the time, they will come in and put a 208 ?? service in for free. He stated that this would allow me to use all my breaker spaces. Could this be an easy fix for my issue?

Thanks,
Donovan
 
Re: Older panel and problem

What did you measure on the 240V circuits?

With the center-tapped delta 120/240 3 phase service, the three insulated lines coming into the building will measure 120V to neutral or ground on 2 and the 3rd will measure about 208V. Voltage shouldn't change within the building unless there is a transformer set to change it or the loads "pull" it down. The voltage of the 3 lines measured line to line (A-B, B-C, C-A) will all measure approximately 240V and should be equal within a few volts, so I wonder why your "220/240" was reading wierd as well. That makes me wonder about the multimeter. Neutral problems do not affect the "220" either because the 230V circuit doesn't use the neutral.

I think the usual procedure now with one of these services is to pull out the single phase circuits into a subpanel to keep it separate from the 3 phase and not have the possibility of getting on the high leg by mistake.

If the other shop's panel was miswired, it wouldn't affect yours at all, from what you describe, yours is miswired, and maybe theirs as well. Just because all the B phase breakers are missing doesn't mean the high leg is the B phase any longer. It may have gotten swapped inadvertently during repairs to the service at some point in the past.

I doubt the utility is going to be ready to change out your service unless there is a problem with their equipment. They could have decided to eliminate all the delta services or some such thing :roll: .

You may not really want this done if you have 240 Volt equipment that wouldn't do well on 208V. 120/208 3 phase is great for buildings with a lot of 120V lighting and outlet circuits and where the other larger equipment was designed for the 208. Usually it is older, heavily loaded, 230V single and 3 phase motors which may have problems with the 208V service. Newer equipment is frequently rated for 208/230 and the main thing to have checked out would be the amperages on the wires to the (now)208V equipment loads.

I still think there could be another problem if the "220" is not something like 230-240.

Jim
 
Re: Older panel and problem

Originally posted by EDC:
Lastly, I also gathered from this electrician that power companies don't like this kind of service and that, much of the time, they will come in and put a 208 ?? service in for free. He stated that this would allow me to use all my breaker spaces. Could this be an easy fix for my issue?

Thanks,
Donovan
Click to expand...
The easiest solution is to get the electrician to make sure that all 120V receptacles are off that high leg. Moving a breaker is a lot easier than swapping out a power company transformer. :)

Now you are the wiser, be sure to double check all the receptacles in your shop once the work is "complete." :D
 
Re: Older panel and problem

just out of curiosity could he have a bad neutral connection? I know I once did an addition to a house that had 180v on one phase and 90v on the other phase after scratching my head I figured out that the aluminum neutral had basicly distinegrated and thus there was not enuff of a connection on the neutral bar
 
Re: Older panel and problem

Donovan, many times, the serving electric utility will use just two transformers to provide a 3?, 4w, 120/240 volt service. In order to provide a 208Y/120 V, 3?, 4w service, the transformers would have to be replaced with three transformers, the bank rewired, and all of the units that are served by the transformers would have to be rewired. We have done that in the past but not without charging for the work and material involved. :D
 
Re: Older panel and problem

O Geez.... I embarassed to say that the verdict is in and I have a fried multi-meter.

Thanks for all the comments.

Donovan
 
Re: Older panel and problem

Best kind of problem to have as long as it doesn't lie and tell you there is no voltage! But seriously an unreliable meter is dangerous.

Lot cheaper than the real problem anyway.

Jim
 
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