Domestic electricity supply voltages in UK

[old martParticipant @oldmart]

[old martParticipant @oldmart]

I thought that the single phase voltage throughout the UK is 230V. But I have just been reading about a Lidl welder which uses flux cored wire on their website which mentions it being unsuitable for use in some low voltage areas.

It says: "not intended for use in residential areas where the power is supplied via a public low-voltage supply system".

Please explain what this means.

[Stuart Smith 5Participant @stuartsmith5]

If you do a search on this forum you will find discussions about this topic before, though I think the last one was about their plasma cutter which had the same message.

The next comment on the Lidl website explains it:

• Both conducted and radiated interference can make it difficult to ensure electromagnetic compatibility in these areas

I bought one last year and it is fine, though it is a different model.

If you do look at the previous discussions, you will find a variety of opinions from the ‘don’t worry it will be ok’ to the ‘ it is illegal and you shouldnt have one because it doesn’t comply with some regulations on emissions’.

As a retired electrical distribution engineer, my view is that you don’t need to worry. 

Stuart

Edited By Stuart Smith 5 on 23/06/2023 19:49:00

[Michael GilliganParticipant @michaelgilligan61133]

It means exactly what it says, I’m afraid

… whether you decide to ignore Lidl’s intention is not their problem

The issue was discussed in some detail, in this thread about the Plasma Cutter:

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=177013

MichaelG.

.

Stuart beat me to it …

Edited By Michael Gilligan on 23/06/2023 19:47:02

[Robert Atkinson 2Participant @robertatkinson2]

Basically this is Lidl's way fof saying that the welder is for industrial use only. This is because it does not meet the requirements ofr interfernce and other distubances it causes to the mains supply for domestic uses.
There are two sides to the interference coin. emissions and susceptabilities. There are standards for both the level of emissions an item can produce on the supply and the levels on the supply at which it must work. Typically the emissions levels are about 1/10th (-10dB) of the susceptability levels to give a working margin. There are different standards and levels for different applications. For example industrial, commercial and domestic. A industrial standard may allow 1000 times (30dB) higher levels than a domestic one. Industrial power supplies also have different standards.
So if you operate the welder on a domestic power circuit you will interfere with others connected to that supply. You may even damage their equipment. They probably won't know what the cause is.

Technically illegal too but unlikely to get caught or sanctioned. However if you happened to interfer with something that caused someone injury or worse you might.

Robert.

[Maurice TaylorParticipant @mauricetaylor82093]

Hi , what happens when small industrial premises are mixed with domestic premises, won’t they be connected to the same power supply as the domestic premises , won’t the interference go to the domestic premises.

Have the industrial premises got filters to prevent this ?

Maurice

[Anonymous]

Posted by Maurice Taylor on 23/06/2023 20:48:32:

Have the industrial premises got filters to prevent this ?

For welders radiated emissions might be more of a problem than conducted emissions.

Andrew

[Chris Pearson 1Participant @chrispearson1]

Posted by old mart on 23/06/2023 19:34:19:

Please explain what this means.

What what means?

LV is between 121 and 600 V (to ground). HV is anything above that, but usually 11 kV (between phases, there being no neutral) at the local transformer. The harmonized (CENELEC) nominal is 230 V, with a range -6% to +10%.

[Robert Atkinson 2Participant @robertatkinson2]

Posted by Maurice Taylor on 23/06/2023 20:48:32:

Hi , what happens when small industrial premises are mixed with domestic premises, won’t they be connected to the same power supply as the domestic premises , won’t the interference go to the domestic premises.

Have the industrial premises got filters to prevent this ?

Maurice

If the supply cable from the low voltage (240/415 Volt) transformer is shared by domestic and commercial customers then all of them should only use equipment approved for domestic supplies. A commercial user would have to pay for a different connection to use industrial equipment. Large users or groups will have a dedicated transformer.
Fo small industrial users the impedance of the two cables and low source impedance of the transformer provides adequate isolation between industrial and domestic users. For large users two thransformers and the high voltage supply provide further protection.

Robert.

[Maurice TaylorParticipant @mauricetaylor82093]

Hi Robert, Thank you for your reply.

Maurice

[old martParticipant @oldmart]

I see, the possibility of some sort of interference rather than a domestic voltage lower than 230V is what Lidl are trying to avoid possible litigation over.

When I bought the VFD to use on the Tom Senior mill that was being restored for the museum, I made sure it had interference filters built in to reduce any problems and it certainly does not seem to affect radios being on in the workshop.

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