UK supply voltage tolerance

I'm sure there's one or two electrical boffins on this NG so I wonder if one could help please?
I've been searching the www and I've found two sets of limitations, I can't
actually decide for certain which is now correct due to the shear mass of info out there.
I've found 230V +10/-6% (216-253) and 230V +/-10% (207-253)
What's the correct answer? The next stage for me might be to get the electricity supply company to install a voltage recorder, I'm suffering from voltage dropping down to around 200-210v when I have heavyish loads on (mainly heating) in the workshop.
TIA Julian.
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wrote:

Sounds like the cabling to the workshop is too wimpy, resulting in a voltage drop from the original supply voltage when you draw heavy loads. Try measuring the supply voltage at your main fusebox under the same load conditions & see what that is like - if the voltage is good there, then its your cabling that is at fault, not the supply.
Regards, Tony
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I'm ahead of you on that one, the workshop is supplied with 6mm SWA and I'm only loosing around 2 volts between dis board and workshop. Thanks for the reply but have you an answer to my initial question?
Julian.
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wrote:

I believe that the situation as far as the UK supply is concerned is that it is required to be 230 -6%/+10%, and for the rest of Europe it is 230 -10%/+6%. This was carefully chosen for minimum impact on the power generators and maximum impact on the equipment manufacturers while still pretending that we have EU harmonization.
So where the 230 -10%/+10% variant that you have seen comes from is that this is what equipment manufacturers potentially (sic) have to handle if they are building products for the EU market.
So if the supply voltage at the company fuse is dropping below that range (less than 216) then it is out of spec.
Regards, Tont
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It was dropping below 200V last Sunday evening when the wife was cooking the roast and I had about 6KW on in the workshop - I guess that they are allowed to let the voltage drop below tolerance for short periods due to heavy demand on the grid - a voltage recorder is the answer, so long as they do it FOC!
Julian.
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Tony Jeffree wrote:

Tony - I thought the +/-10% limit came in 1st Jan 2003 - but I stand to be corrected. My copy of the 16th Edition is pre 2003 and says it is 'due to change' on that date.
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Lester Caine - G8HFL
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Lester Caine wrote:

OK - I can correct my own statement ... The +/-10% change was postponed until 1st January 2008 - and then was postponed indefinitely ... So the lower limit IS 216V for the UK currently ;)
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Lester Caine - G8HFL
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wrote:

Yep...but as I said, if you are building product for the EU market then your products have to handle the full +-10%.
Regards, Tony.
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Tony Jeffree wrote:

Most of the power packs I'm using now do 95V up ;)
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Probably switchers on the input, boosting up to 400V from which the switcher that creates the output is driven. A ruse to reduce the PF of the PSU, so that power is absorbed for most of the input 50Hz waveform, thus removing the nasty harmonic spikes caused by peak conduction of diodes that feed smoothing capacitors.
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Good, so I've got 'em by the short and curlies it would appear.
One of the most noticeable problems with low voltage is my old ''buzz box'' stick welder which seems to make a habit of extinguishing the arc at random - my newer ''inverter'' style welder does not suffer this problem. The fluorescent light tubes often extinguish and then strike up again when I start equipment that takes a big initial surge of current like the big angle grinder.
Julian.
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Are you single or three phase? if single phase, what are the neighbours on the other phases seeing (eg, general low voltage or one over loaded phase)?
What is the maximum voltage you ever get? If it's below 240, a tap change may be simple, if much above that, they may be reluctant.
6mm Pah! I've got 16mm 4 core SWA (still no 3ph though :)
Mark Rand RTFM
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wrote:

neighbours on the

phase)?
change may

...pah! 16mm 4 core - baby stuff <G> 160 amps per phase three phase wired in 120mm entering workshop (but the plonkers EDF have fed it with 6mm diam (28sq mm cross section) aluminium overhead - no doubt it'll melt some time soon!)
AWEM
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On Wed, 3 Feb 2010 20:32:33 -0000, "Andrew Mawson"

My logic was that if I managed to use all 63A 3ph in my little shed, I wouldn't have a shed any more, I'd have a small mushroom cloud :-)
Mark Rand RTFM
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...pah! 16mm 4 core - baby stuff <G> 160 amps per phase three phase

pah! 120mm 4 core - baby stuff.
185mm - 4 core-315 amps a phase
Mark.
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Swank <G>
AWEM
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But your factory is about 10 times the size of my house, garden, neighbours house, their garden and the road inbetween!
Charles
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wrote:

We are single phase. We have a single phase 11KV (I think it's 11KV) supply to a transformer mounted up a pole in the garden, this transformer supplies just me and the neighbour from its single phase output. I think the root cause of the problem is this antiquated transformer which almost certainly dates back to the days when national grid electrickery first found it's way out into the countryside.

I've never seen anything like 240 volts - chance would be a fine thing :-) I'll be contacting MANWEB on Monday morning to see what they say on the issue.

I don't think the board's cable from the transformer to the meter is much more than 6mm :-(
Regards Julian.
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Lester Caine wrote:

I've seen about 150V on my supply on one occasion for a few hours and my neighbour has seen it some years prior to that. He took it up with the utility the first time and their response was it couldn't happen as they had things in place to prevent it due to the danger it could cause. I took a reading to verify and turned off things like the fridge, most bulbs glowed dimly, flourescents varied from dim to OK depending on type. I ended up watching TV in the dim light as it must have had a universal supply and was unphased.
Any ideas about the regs requiring cutoff of supply in low voltage conditions.
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On Wed, 03 Feb 2010 23:30:05 +0000, David Billington

The statutory limit is just that. Brownouts should never occur in the UK, since the utility should cut the power completely rather than go below the limit. Obviously this isn't necessarily going to happen if there's a fault in a local distribution transformer, or a neutral cable gets an open circuit fault.
Mark Rand RTFM
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