Mains voltage 275v??

[Steviecuk]

Hi all. I have just installed some lighting in my lounge which is a mixture of LED tape via a dimable transformer and LED GU10s all run through an LED comparable dimmer switch.

Information that you might need to know.

I have removed the original light fitting in the middle of the room and connected the loop through and patched the whole up. As I am using a transformer for the LED tape and wanted to add a plug socket in the loop for something else, I decided to run the power to the new lighting run from a fused spur that was on the back wall. The fused spur is on the main downstairs socket loop and because of this and because I was fitted a plug socket with the run, I used 2.5mm T&E for the run (nightmare trying to get it into the GU10 holders)

Everything has been working absolutely fine for about two weeks until I noticed the LED tape not working this evening. I have checked the tape and it is not receiving its 12v and is steady at 0. I then removed the transformer cover and measured nothing on the output side, however measured 278-282v on the input from the dimmer. I measured direct from the dimmer and the input to the dimmer is the same. When the dimmer is low the output voltage is 105v.

My question is why the hell do I have 278-282v going to the dimmer and in turn to the transformer? The transformer is rated up to 240v which I'm guessing would have a little bit of leeway but probably not up to 280v and I am presuming this is what has blown it. I have measured a plug socket on the other side of the room but should be on the same loop and that is measuring 253v.

Can anyone tell me why there might be this stranger higher voltage?

Thanks. Steve.

 

[dmxtothemax]

Any piece of kit sold in the UK should be OK on 248V. Many will survive operating at 260, 270, maybe even 280V. If it went pop purely because of the presence of 248V I would want my money back.

My mains is often above 240V, I operate hundreds of pieces of sensitive and expensive electronic equipment and I certainly wouldn't bother with one of those optimiser things. I only measure it out of interest.

Nice pic Lucien !
Haven't seen a mercury arc rectifier for a long time
it's one thing you never forget
the UV given off must be off the scale.

 

[Steviecuk]

what happens to the voltage if you place a decent load on the socket ?
does it stay high or go down/away ?

It stayed the same. However the electricity board came out and concluded that it was my meter that was up the duff. His proper one shower the mains voltage as 248v and said I must live near a sub station and that those levels were fine. New multimeter for me I think.

 

[Darkwood]

I don't know who you talked to at the place you got your transformer but to distribute any electrical items within the UK they are required to work on our mains voltage (nominal 230v in your case), this includes the allowed tolerances for which our supply is legally allowed to fall within (mentioned earlier). The company that sold you the TX may not understand this as they maybe just distributors and not savvy in electrical talk, it also be the case they maybe one of the many distributors out there that are importing cheap chinese rubbish which is falsly CE marked. I take it your product is CE marked?... if so then it should work comfortably at 248v.

 

[snowhead]

I take it your product is CE marked?... if so then it should work comfortably at 248v.

The Chinese put C.E on everything to indicate "Chinese Export" (allegedly..)

 

[Darkwood]

The Chinese put C.E on everything to indicate "Chinese Export" (allegedly..)

Yes this has be mentioned before but the symbol CE users is copyrighted and cannot be confused with CE if they put it on for any other reason, it is down to the distributor to ensure a product from outside the EU is compliant and this means it should be tested and checked by a third party to assure it meets all standards, with big international companies this is easy as their brand name often is good enough but China is one of the biggest black markets for fake goods in the world so it all needs independently varifying.

 

[Steviecuk]

It was a reputable place called Tagra and have their branding on the tx. I have bought cheap Chinese ones before and this was definitely of better quality. The electric guy said it might be EU spec as he thinks they have a slightly lower voltage as standard. It was rated at 200-240 my one. The company said 'oh we have never had one back before'. I said well you have now.

 

[Steviecuk]

Consequently I have only been able to fine one UK company that does a constant voltage 12v 50w mains dimable driver that works 220-250v. Everything else is 220-240 and can't risk running with my 248v house mains. I found one the other day marked '230v 10%' but then realised it was 12v AC output, not DC. Was only £7 too. The one I mentioned above is £35!!!

 

[Darkwood]

Anything sold within the UK has to be compliant with our nominal voltage and the legal tolerances that the voltage may exist at, the lables on many electrical good only state the nominal voltage but by design they are required to allow for the 216v-253v (if I recall correctly) that my be present.

 

[Steviecuk]

Oh right. So maybe it was a faulty individual tranny then as it was labelled 200-240. On the input side of the transformer, there was a capacitor looking chip with 135 degrees on the side. I don't know if it was a capacitor or an overheat protection type thing. Either way, this had burn out. I presumed from the 248 V input.

 

[Steviecuk]

216v-253v (if I recall correctly) that my be present.

Yes the National Grid guy said it should be 230v +10% to -6% so you're spot on.