Tolerance

[jxofaltrds]

On a 110 outlet what is the allowable voltage.

120.0 +/- what?

I measured 125.2 and it kept shuting my Suretest down.

Finally got it to trip the AFCI's.

Mike P.

 

[charlie]

Re: Tolerance

Only the old timers (I qualify) are permitted to use 110 or 115 volts to refer to receptacles.

Most electric utilities are required to provide electricity in a range from nominal. In the USA, the nominal is 120 volts and most of the time it is plus or minus 5%. That would give you an acceptable range of 114 to 126 volts.

We use substation transformers and voltage regulators that are set to put out 13.8 kV and our nominal distribution voltage is 13.2 kV. Our 7.62 kV transformers that are located close to the subs and regulators are running on the high side of nominal.

 

[Guest]

Re: Tolerance

I'm old enough to wrestle with that issue all the time. In my mind it's 110 and 220, but when I post things or talk to somebody I try to translate that to 120 and 240. It must be like knowing two languages. You think in one, and speak in the other.

With the 5% rule 110 and 220 don't even make the grade any longer

../Wayne C.

 

[big john]

Re: Tolerance

Around northern Virginia, for residential at least, the POCO accepts anything within 10% of nominal. You might be getting anything from 108 through 132 out of a receptacle and that would be a-okay by them. :roll:

A side note: In a lot of foreign countries, isn't 220 actually one of the nominal voltages? It just screws you up even more in these message boards: They say "220", you correct them with "240", come to find out you were wrong.

-John

 

[jxofaltrds]

Re: Tolerance

Thanxs guys.

I am I not clear on why it would effect my tester. It is suppose to work within that range.

Anyone else had a problem with the SureTest? Or could another problem be causing this?

Mike P.

 

[iwire]

Re: Tolerance

I was trying to find ANSI C84.1(1) on the web but you need to pay for it.

This is from a POCO Web site, it appears to be at least some of the standard.

You would need to talk to your POCO to see if they follow this standard.

Voltage Range
The American National Standard ANSI C84.1(1) establishes nominal voltage ratings and tolerances for 60-hertz (alternating current, AC) electric power systems above 100 volts and through 230, 000 volts.

Voltage operating ranges are recommended for two voltage categories:

1) the service voltage, typically the point of connection between utility and customer; and

2) the utilization voltage, typically the termination point to equipment. The utilization voltage range takes into account a voltage drop within the end user?s distribution circuits.

ANSI C84.1 expects equipment to operate at service voltages between 95% to 105% with a utilization voltage range of 87% to 106% (120V to 600V)

Refer to ANSI C84.1 for additional operating voltage ranges).

You can see the source here

Bob

[ September 09, 2003, 06:02 PM: Message edited by: iwire ]

 

[brian john]

Re: Tolerance

Big John:

I do a lot of power quality surveys in No VA and generally find ranges between 115 and 125. I believe Dominion Power is plus or minus 5% on nominal 120 VAC.
There are stipulations for residential in rural locations as compared to urban settings.


http://www.dom.com/customer/pdf/va/vatc7ra.pdf

Where are you in NO VA?

 

[brian john]

Re: Tolerance

Those standards are at the POC/delivery point, what the customer does with the + or - 5% (114-126) is an other thing.

 

[big john]

Re: Tolerance

Brian John,

I was in Alexandria, right outside D.C. The 10% tolerance I gave came right from the horses mouth: Got that number from talking to two separate Dominion trouble crews on different occasions. This was some years ago (right after "Dominion" replaced "VEPCO" on the service trucks) maybe standards have tightened up since then?

-John

 

[charlie]

Re: Tolerance

Originally posted by Big John:
The 10% tolerance I gave came right from the horses mouth: Got that number from talking to two separate Dominion trouble crews on different occasions.

Sorry, Big John, you are talking to the wrong horse. Look up the permitted voltage range, by the public service commission in your area.

I assure you that our linemen do not know anything except we are permitted 5% deviation from nominal. We are permitted more in rural areas. Additionally, we are prohibited from having too many dropouts and other interruptions.

 

[brian john]

Re: Tolerance

Big John:

It would be 10% if you consider 5% + or -. A 10% window.


Most cases of low voltage (as are most PQ issue I've run across are customer induced.

 

[big john]

Re: Tolerance

Brian John,

I'd be willing to bet you're right about it being a window. I'd just always assumed they'd meant 10% above or below nominal. We all know what they say about assumptions...

You've piqued my curiosity now: What in the world have you seen homeowners do that would cause unusual voltage variations at their service?

-John

 

[jerry peck]

Re: Tolerance

Mike P.

Sounds like there might be a problem with your SureTest. One of the new ones by Ideal, or the older ones, like the STD-1?