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Electrical concern about voltage?
I've never encountered this before and am having trouble finding definitive assurance of what to do about it...
I've been asked to run wires for temporary electric heaters in a Church, and they only come in 3 phase 208/240/480 volt options.
They do have 3 phase service, technically it's 240 volt Wye (neutral is not isolated, it's the middle leg)
Anyways, when I put a tester on the mains, I'm reading 260 volts between them.
I contacted the supplier of the heaters and asked for a technician to advise and he was certain that the units could be damaged by that difference... 20 volts over the rated. I figure that most devices running on 240 volts are rated for 250 volts max.
It's inductive heating so I can't imagine it hurting the elements but the thermostat might arc and start a fire.
I'm wondering if anyone out there has experience with this, who can tell me it's certainly fine and nothing to worry about, or that I need a voltage regulator or resistor to bring it down closer to 240.
The big problem is, they sprang this on me last minute this afternoon, not giving me nearly enough time to estimate and gather supplies, but need it done before Sunday morning's service...
No suppliers are open on the weekends. Home depot and Lowes really don't accommodate commercial work.
Any insight?
I am a certified journeyman electrician working under a master electrician licensed and insured in the state. This is a temporary set up. I was able to work it out and the supplier of the heaters agreed that they should have a 10% tolerance. After I set everything up, tested everything, and then turned them on, they had no trouble whatsoever and brought the voltage down to about 252 at the source pulling the full 80 amps of load. So apparently not having any load plays a factor in the service voltage being high. At any rate it was a very good experience and quite fortunate the way things worked out. I'll be returning today to collect payment (rather compensation for materials and very little left for labor...) and ensure everything worked through the night as expected. Then on Monday I will pick up some more appropriate components (further depleting any profit/income) to replace what I had to use to make it happen. We'll not go into details about that except to say that it is p
4 Answers
- steve hLv 68 years agoFavorite Answer
Most electrical devices are designed for plus or minus 10% of the rated voltage.You should be fine.
Source(s): Old guy - tom7railwayLv 78 years ago
Unless you are a certified contractor it is illegal to do any wiring whatsoever.
Even if YOU are legal it can't be done legally in such a short time without an inspection
Just tell them NO you can't do it. I would suspect a faulty meter, I never saw an installation which is 20 volts above mains voltage.
The only thing you can legally do is wire each heater to a 13 amp plug and power the heaters from sockets. A church will take a lot of power to heat it and each ring main circuit can only supply about 7 Kilowatts. Or to put it more simply, 2 x 3kw fan heaters.
The simplest thing to use would be a gas space heater which burns gas and has a powerful fan, it is at least 10 kilowatts of heat but probably less than 500 watts for the fan. You could use 5 or 6 of them safely on one socket circuit. Probably too late now though, tell them to wear their long johns.
Source(s): ex-electrician - GTBLv 78 years ago
It is very clear to me that you do not understand 3 phase wiring.
This project is NOT the way to learn how to do it. I do not care how urgent the issue is this is not the project for you to take on without experienced and trained people.
Despite the desire to have it working on Sunday for services, improper wiring can easily cause fatal disasters.
Surely someone in your congregation runs an electric company and can be brought in to assist.
Because any suggestion I make to you will likely be misinterpreted I will not comment on how to address it. Just get competent help
Source(s): I am an engineer - Anonymous8 years ago
That is not a job for an amateur. You need to hire an actual electrician so he knows stuff like that, and you have someone to sue if it's done wrong.
