Shower causes lights to dim

[davidgreene]

my halogen downlights have always dimmed when shower running, same way my site lite sometimes goes off for a sec when using a mitre saw or something similar,

 

[ban-all-sheds]

You should have a competent electrician check your installation out, just in case there is something wrong.

 

[janner10]

It's not dangerous or anything to worry about.

I disagree - it might be, and should be checked out for peace of mind - if there's a poor connection with a high resistance in the cutout/meter/CU then bad things can happen.

It's very rare to see an electric shower that doesn't casue the lights to dim. I fitted hundreds of showers into disabled bathroom conversions for Leeds city council. Every one of those houses / flats must have had a high resistance joint on the incommer.

It's great knowing the theory, but things are different when you get out there working on installations in the real world.

Sadly not many on the forum do - there's a lot of armchair electricians here.

 

[JohnW2]

It's great knowing the theory, but things are different when you get out there working on installations in the real world.

Sadly not many on the forum do - there's a lot of armchair electricians here.

True, but I'm not sure it's sad - have you noticed the name and purpose of this forum?

In any event, there is not usually any lack of people advising that testing is required in order to confirm that some very unlikely problem is not present, so I'm a little surprised to see a change of attitude in relation to the scenario being discussed here. Sure, there's probably a 99%+ chance that the dimming is not due to any wiring fault or poor connection - but, in most people's hands, there is probably more than a 99%+ chance of there being no wiring fault or poor connection after, say, a socket has been added to a circuit (or, indeed, a whole new circuit added). Just because there is a common, non-problematic, probable explanation for the dimming does not mean that it can't also be produced by a problem.

Kind Regards, John.

 

[ban-all-sheds]

In any event, there is not usually any lack of people advising that testing is required in order to confirm that some very unlikely problem is not present, so I'm a little surprised to see a change of attitude in relation to the scenario being discussed here.

True.

I wonder how many of the "non-armchair" electricians here go for years without finding any problems with their installation work, but still test every time?

 

[JohnW2]

True. I wonder how many of the "non-armchair" electricians here go for years without finding any problems with their installation work, but still test every time?

Indeed - and we know that pilots rigorously go through their interminable list of pre-flight checks despite knowing that they may well get through a whole flying career without such checks ever revealing any life-threatening problem. When it comes to any safety-critical situation, the fact that things are 'nearly always OK' is a pretty poor excuse for not undertaking checks/tests ... in my opinion, from my armchair!

Kind Regards, John.

 

[ban-all-sheds]

Did you check that none of the legs had developed a potentially catastrophic crack before you sat in it?

 

[JohnW2]

Did you check that none of the legs had developed a potentially catastrophic crack before you sat in it?

Nope, but the airmchair on which I'm sitting has legs only about 3 inches long, so I know there is no meaningful risk of any catastrophe. ... but you're at risk of undermining 'our' side of this argument!

I'm sure no-one is suggesting that there should be any concerns if turning on a shower has caused lights to dim 'for years'. However, if there is marked dimming when a newly-installed shower is switched on or, far more important, if dimming suddenly starts occurring ('for no apparent reason') after having previously not been experienced, then surely there is a strong case for 'testing to be sure'?

Kind Regards, John.

 

[westie101]

I'm sure no-one is suggesting that there should be any concerns if turning on a shower has caused lights to dim 'for years'. However, if there is marked dimming when a newly-installed shower is switched on or, far more important, if dimming suddenly starts occurring ('for no apparent reason') after having previously not been experienced, then surely there is a strong case for 'testing to be sure'?

And that apparent lack of information is part of the problem. Reading the OP again it seems, to me, to imply that it is not a new problem but does not give any information of the degree of dimming.
The sort of situation that leads to a lot of interesting call-outs

 

[ban-all-sheds]

It would have been prudent to ask if it was new behaviour - I just assumed that someone wouldn't post here asking about it unless either it had started recently, or had "always" done it but "always" was a short time because he'd not been in the house for long.

 

[conny]

Whilst not being an 'electrician', just a mere electrical fitter, many years ago I was asked to look at my in-laws neighbours electrics because they had this problem. It was a new installation by 'a friend' of the family so after isolating and checking the connections to the shower were correct and tight I decided to trace the route of the cable for any JB's that he might have used. I didn't find any but did discover he had wired it into a bedroom ceiling rose! He managed to squeeze the 6mm L & N into it but terminated the 'bare' earth to and old stranded earth wire running through the loft. On checking the fuse board, (Wylex rewireable type), he had used 30A fuse wire in a 5A lighting circuit fuse carrier. I disconnected the cable from the rose, rewired the fuse with 5Awire and told them to call MANWEB in to do it properly.

So in my opinion, get it checked and tested by a qualified spark/company, if only for your own peace of mind.

 

[bernardgreen]

My in-laws had a family member, a quaified electricians mate, wire in a 13 amp socket for the electric fire and and immersion heater. He left the instruction not to have the fire and the immersion heater on at the same time. Both new circuits were supplied as spurs from JBs on the rubber cable feeding a 15 amp socket. The lamp for the glass "lean to" conservatory was also fed from the same cable.