ECN Forum Forums General Topics of the Trade General Discussion Area 130 Volt Residence

Thanks Dereck, I didn't have a clue how they did it. I do know that the trouble men have to have their meters calibrated on a regular basis (please don't ask how often, I just know they have to do it).

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Charlie Eldridge, Indianapolis, Utility Power Guy

The utility I work at set the limits for voltage at 95% to 105% or 114 to 126 for a 120v feed, we measure the voltage at the line side lugs of the meter socket.

I'm curious is the service is 120/240 & if so, what is the line to line voltage? I've seen weak nuetral connections cause the voltage on the lightly loaded leg increase to 130 - 135 and the voltage on the heavily loaded voltage drop to 105 - 110.

At our utility, a high voltage or low voltage complaints are resolved as soon as possible, if not same day, due to the damage that can be done to the customer's equipment. Also, most public service commisions require the utility to provide "correct voltage" to a customer or be responsible for damages. (We interpret correct voltage as the above stated range.)

We're pretty fortunate in England in having a fairly stable supply in most areas compared to some countries. For many years, the statutory standard has allowed a 6% variation from the nominal 240V.

Certainly in my area it's only on very rare occasions such as during storm conditions that I've seen it drop below the minimum limit, and I don't think I've ever seen it exceed the maximum. I think once I registered about 252V, but most of the time I never see higher than about 245V absolute maximum.

 
Voltmeters “fresh out of the wrapper” have a range of accuracy, and taking the time to understand that characteristic for digital instruments measuring AC voltage can keep a foot out of your mouth.

Many utilities have their ‘service conditions’ or ‘electric rules’ posted on their websites. A North American standard that is often cited is ANSI C84.1, but a state PUC may mandate tighter extremes than published in C84. For a 120-volt base, usually 126 or 127 volts is the upper [sustained] limit, but certain regions limit it to 125V.

If a trouble guy comes out to check voltage, ask to compare your readings to his with both meters simultaneously connected.

Dave, I would have left it in the customers hands too.

The last sceduled disconect I had with Com Ed they were to be there at 8:00. We were early and ready for them. They came a bit before 12:00. They question your need for disconect and say "well a lot of EC will just pull the wires hot thru the meter and underground conduit but if your scared we can disconect for you". No garentees on reconect time but should be some time tonight. We do a little work and spend a day at the job. Beforehand the customer wants to know why so much. We tell them cause we spend most of a day messing around with Com Ed. The customer is not happy because we left them in the dark. I tell the they are sceduled for hook up and here is there number. I don't get enough to spend my night waiting for the utility.

I'm not saying their linemen are bad more their service policies.

Tom

PaulUK,

Which area are you in, friend? In Croydon I can go from 255 (yes, above our limit) to 214 (yes, below our limit) in 30 minutes! I've got recordings of this (done with 3 separate instruments - just to be sure to be sure). Count yourself exceedingly fortunate! (but, then again, at 245 average, you must be spending a lot on light bulbs!).

M.

Hi Marc,

I'm in rural Norfolk, on the coast about midway between Cromer and Gt. Yarmouth.

Maybe it is surprising how well-regulated the supply is here, considering that we're right out at the extremities of the 11kV distribution. Against that though, there are almost no heavy industrial loads in the immediate area, and the sub-station feeding my little settlement has nothing but domestic loads and maybe a small 3-ph motor load at the water pumping station.

Not average. 245 is about the highest I've seen in the immediate neighborhood under normal conditions. That time it went over 250 was very unusual. The average is probably more like 238V.

I've been keeping a eye on the line voltage while working at my desk this afternoon:
It's now 4 p.m. Sunday, and the line is at 239V, up from a low of 234V around 1:30 p.m.

Is your area maybe suffering from excess demand? It sounds as though the PoCo might have notched up a tap or two on the transformer to compensate at peak demand times, leaving you with an idle voltage in excess of the limit.


[This message has been edited by pauluk (edited 11-07-2004).]

PaulUK,

You're exceedingly fortunate! Sorry, yes, read the post wrong while dashing out the door for a flight to Scotland (had I known where you were, would have waved!).

Yip, we just ain't got enough copper in the ground to sustain all the houses in the area. As is, my average (and this is meant as average) is up beyond 240; I think this is to try and keep the voltage falling too low when demand kicks in.

As for high voltages, had a friend ask if there was something he could do to stop buying light bulbs as often as he was (and he was obeying all the rules regarding good quality etc.), so put the following together for him. http://www.marcspages.co.uk/pq/?6620 - I suppose it breaks a shed-load of 'codes' and/or regs, but it worked for him!

M.

About 12 years ago I happened to find that my powerline voltage was 132V. And twice that across both phases, so it wasn't a bad neutral. Called the POCO, and got the usual not knowledgable customer service rep. "Are the lights on? Yes. Then what's your problem?" I got her to pass a note to their linemen that the voltage here was too high. Well a few weeks later 2 linemen show up with a digital voltmeter and sure enough the voltage is too high. They pulled the cover off the meter, and it's too high there too. They visit the local substation, find a few bad capacitors, replace them, still the voltage is too high. Turns out the 3 phases feeding the entire town was not loaded evenly. It took about 6 weeks to get it all fixed.