How to test for correct voltage (diy)

[Christopher Parkinson]

(DIY) Hi, I suspect that I'm not getting the correct 230v in my premises. How likely is it that voltage supply could be less than 230v? What equipment would I need to test it?

 

[snowhead]

What issue have you got leading you to think that and do you live in the countryside or in a town /city?

The voltage may be above or below that , providing it's within the set limits it's O.K and everthing should work O.K

 

[Lucien Nunes]

The easiest and safest method is to buy a plug-in power monitor that includes a voltage display mode. If you plug it into a circuit that does not have much load on it, then it will fairly accurately reflect the supply voltage, subject of course the the product's own accuracy.

Supplies in the UK are permitted to vary between 216 and 253 volts and all modern equipment is designed to accommodate this range, although the lower extreme is rarely found. A further 5% drop is permitted in the wiring of the building (except on lighting circuits where it is 3%).

 

[littlespark]

Sorry to be pedantic, @Lucien Nunes but it’s 216.3v lower limit. (230 - 6% or 230 + 10%)
Last eicr I did was bang on 216, so advised customer to speak to their supplier.

OP. Is there an issue? Such as fluorescent lights struggling to start?
If you want to know a definite voltage reading, you will need a calibrated test instrument which most electricians have access to. A cheaper version may not be as accurate as you need it to be.

 

[telectrix]

was on a job to a client some time ago. office from home.round about 4.30pm florries flickering. checke cit=rcuit, no faults found. then meter on incoming supply.... 204V. contacted SP. to be told that client was on end of a long rural run, can't do anything about it unless cusomer pays for new supply. on investigation by SP, was determined that a new 1 phase supply would not cure the problem. ended up with a 3 phase supply, 400 m from nearest pole transformer, . customer dug trench. still cost him £15K. then my costs for a 3 phase board and all the additional equipment.

 

[R-fur]

Tel SPEN were out of order there. They have a duty to maintain the voltage within limits, as long as the customer has not increased his load without SPEN permission. I usually advise them to write to the DNO with a registered letter. The DNO have set time limits to respond (6 months I think).

 

[Risteard]

Sorry to be pedantic, @Lucien Nunes but it’s 216.3v lower limit.

It's 216.2V actually.

 

[Pete999]

It's 216.2V actually.

And to think I have been accused of being Pedantic!!!!

 

[Lucien Nunes]

Knowing the RMS value of an approximate-but-not-perfect sinewave (that has a -10/+6% tolerance on nominal) to 4 significant figures is not especially useful. I've just measured the diameter of my biscuit with a Trimos electronic height gauge as 66.318 mm +/- 2.5μm. Making the measurement to this precision is not helpful because:
a) The biscuit is out-of-round by ~2mm so the implied precision of diameter is unrealistic
b) There are crumbs all over the optical surface table.
c) The biscuit tastes of corrosion inhibitor.

 

[littlespark]

Coat the biscuit thoroughly in chocolate. And remeasure

 

[DPG]

Knowing the RMS value of an approximate-but-not-perfect sinewave (that has a -10/+6% tolerance on nominal) to 4 significant figures is not especially useful. I've just measured the diameter of my biscuit with a Trimos electronic height gauge as 66.318 mm +/- 2.5μm. Making the measurement to this precision is not helpful because:
a) The biscuit is out-of-round by ~2mm so the implied precision of diameter is unrealistic
b) There are crumbs all over the optical surface table.
c) The biscuit tastes of corrosion inhibitor.

I find Custard Creams to be of particularly poor tolerance. Apart from the British Standard one of course which is held in a laboratory at a constant temperature and humidity. Next to the standard kilogram I believe.

 

[Lucien Nunes]

I'm seeing terrible runout on the custard creams too, heaven knows what kind of shoddy tooling they are using to bond them. We've made a go/no-go gauge to take round to Asda so we can reject really bad packs at source. Even so, one of the lads has to stop his job 10 mins before tea break and true them all up while the kettle boils.

Anyway, sorry, OP, yes, let's hear more about your scenario and observations and we can suggest a strategy for investigating your power quality.

 

[static zap]

Is there an issue? Such as fluorescent lights struggling to start?

They never did like cold kitchens below 10 degrees C !
( As a kid I eventually got tall enough to rub the "Magic"
Kitchen light ) When the Aga was not lit !

 

[Christopher Parkinson]

OK. Well here is the scenario. My premises are on a farm. When I first moved in I had a load of metal halide lamps installed. One by one they all failed. Most of them in about a year. I always suspected that it was because the power supply was dodgy.

I'm currently making a tanning bed which I aim to sell to the US. I've sourced a 110 ballast and I tested it today with a transformer. The lamp flickers. There is nothing wrong with the lamp because it works fine with a 230v ballast. I also checked all the connections. All good. So is it a) the ballast b) the transformer or c) dodgy voltage? The dodgy voltage possibility is the easiest to check I think. I've emailed the ballast manufacturer. I'm waiting for a reply.

 

[Risteard]

that has a -10/+6% tolerance on nominal

Or even a +10%/-6% ;-)

 

[Christopher Parkinson]

Can someone give me a link to buy a
"plug-in power monitor that includes a voltage display mode."

 

[telectrix]

simmple and cheap. a baSIC SOCKET TESTER WITRH VOLTAGE DISPLAY IN WHOLE NUMBERS ( NO DECIMAL POINTS). (AND THE FAT FINGER ON "a" DEPRESSES THE CAPS LOCK. WHAT A STUPID LOCATION.why not put it next to "Q" which is rarley used?

Digital Display Plug Socket Tester Malfunction Detector Mains Fault Checker | eBay

1 x Mains Socket Tester. - Electric Socket Tester - Advanced Socket Tester for quick detection of the correct electrical connection of the socket. Designed using the RCD / GFCI test button - the power outlet is properly wired and the RCD / GFCI trip function.

www.ebay.co.uk

 

[davesparks]

I'm currently making a tanning bed which I aim to sell to the US. I've sourced a 110 ballast and I tested it today with a transformer. The lamp flickers. There is nothing wrong with the lamp because it works fine with a 230v ballast. I also checked all the connections. All good. So is it a) the ballast b) the transformer or c) dodgy voltage? The dodgy voltage possibility is the easiest to check I think. I've emailed the ballast manufacturer. I'm waiting for a reply.

OK, since you are manufacturing electrical appliances you presumably have some electrical test equipment?

 

[Lucien Nunes]

Please post a pic or link to the ballast spec. If it is a US-spec wirewound ballast it will not be suitable for 50Hz operation. The tube will be overrun and the core may saturate especially if the transformer output is high.

 

[dmxtothemax]

why not just use a boost transformer ?
Use this for the critical loads,
And use the low mains for non critical