New RCD tripping. Some questions to help me identify source

The garage doesn't need to have two RCD's in series, protecting it, as then it become pot luck, which will trip.

The immersion heater, will be like mine - just installed as a backup, for if/when the boiler fails. Using it, will cost you 3 to four times as much as simply using the gas boiler, to heat it, assuming you don't have an off-peak rate.
Cheers, I assumed the immersion heater would work along those lines, how do you actually use it though (as in, if I decided that for some reason that I wanted to heat the cylinder off the element, how would I choose to do that? The 30 year old controller I have has a "boost" mode so I assume that would do it?. Also, I take it there's no issue with running the system with the electric heating element isolated?)
 
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Immersion is switched on using the switch on the wall which has the cable going to the immersion.

Other controls are for the boiler, totally separate and unrelated.
 
Immersion is switched on using the switch on the wall which has the cable going to the immersion.

Other controls are for the boiler, totally separate and unrelated.
Hi, thanks.

Yeah I'd just made a post on the central heating forum about this and the same thing was mentioned. Strange thing is though that the isolator is in the in position , as us the switch marked "water heater" in the boiler cupboard but I'm only spending about £2-3 a day in electricity according to my smart meter which makes me think a 3kw heater isn't running constantly. Really weird,infant work out what's going on here
 
The OP said that the cu has just been replaced

So I suggested they got the installer back to investigate
Thanks for the answer.
It is sometimes difficult with the written word to get the same meaning as the spoken word, even then the meaning often is not clear.
I was trying to ascertain if you were or were not automatically attaching some blame to the installer.
As we both know (and probably quite a few others on this forum too) that some installers fall short of doing proper, decent, diligent work, it does happen quite frequently I fear.
However, it does not always follow that, given the info we have, this is the case here. Such installer might have indeed have done a proper job and yet this sequence of events has occurred.
I`m sure we are both aware of some customers getting things a bit wrong with their assumptions and making some incredible conclusions which turn out to be quite wrong.
Such favourites as - My TV set does not work, it worked before you rewired my house so you must have let too much electric thru it. - my daughters TV set does not work on that socket you put in when you rewired the house ten years ago in fact we have never plugged anything into that socket and the last 3 years my daughter was at university (I plugged an appliance into the socket and it worked fine) I opened up the plugtop on that TV and a flexwire dropped out of its terminal, remade the connection and the TV worked fine) - My garage supply has blown a fuse and I can not reset it, its only 4 days since that bloke was hammering on that wall to knock it down (20 foot away) so he must have caused it, that supply has been under my drive for over ten years now so it must be ok! - that supply was a length of 2.5 T&E laid in a three inch deep trench across a driveway with two card driving over it most days, the "trench" was back filled with soil and chippings , how the hell had that cable lasted any number of years under those conditions amazed me.
I`m sure you could add more to the list too.
So I was wondering from your post just exactly the meaning of your answer.
Who knows the likely answer? Was the installer diligent or not? we have no idea at this stage, could be a yes or could be a no. I would be interested to see any test sheet provided, it might give us some clue! It does sometimes .
In fact one firm I know doing loads of EICRs, as soon as I see that firms name on it I suggest that paperwork should be stored in "File 13" , apparently lots of offices have differing names, letters, numbers for their file storage system but "File 13" often refers to The Litter Bin in office speak .
 
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as us the switch marked "water heater" in the boiler cupboard but I'm only spending about £2-3 a day in electricity according to my smart meter which makes me think a 3kw heater isn't running constantly.

The switch in the airing cupboard, is an isolating switch - likely there will be a second switch, often with a warning light, at a more accessible location, such as the kitchen. For the immersion heater to be on, both switches would need to be on.

When actually turned on, assuming the cylinder is below the set temperature, you will here a slight rumble from the element heating the water.
 
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Sounds like it could be heat build up on a loose connection to the busbar. Had this before where it tripped the RCD.
 
Sounds like it could be heat build up on a loose connection to the busbar. Had this before where it tripped the RCD.
Hi, cheers for this. So, just so I'm clear, are you refering to the combing that connects to line side of the MCBs (apologies if daft question, im not massively familiar with setup inside CU)
 
Hi, cheers for this. So, just so I'm clear, are you refering to the combing that connects to line side of the MCBs (apologies if daft question, im not massively familiar with setup inside CU)
Yes.
 
.... I was trying to ascertain if you were or were not automatically attaching some blame to the installer. ..
That's what I assumed. However, 'blame' doesn't really come into it, does it?

If an electrician installed a new CU 'today', and RCD trips started happening later in the same day, the most obvious course would be to get the electrician back (without necessarily any suggestion of 'blame'), isn't it?
 
If an electrician installed a new CU 'today', and RCD trips started happening later in the same day, the most obvious course would be to get the electrician back (without necessarily any suggestion of 'blame'), isn't it?

All my quotes for changing CU's come with warnings about unexpected issues and possible higher costs.

In this case the CU was changed so it makes perfect sense to get the installer back ......... this isn't about blame
 
Yes indeed, that is the way I read it and I realised I might have been me misunderstanding the intention of that post or not, I had no idea and it being such a short comment it was very difficult to decide which it was most likely to be, more so than the spoken word I sometimes think, although once again even spoken words can be misunderstood too, they are not immune.

As an example, some I know got the local authority involved because his ex allowed their children to play in the attic which she had floored out with plywood etc, she told the LA officers it was purely for storage purposes and she had no intention of children using it as a play area, access was via stepladder to the bathroom loft and his biggest concern was a child could fall into the bathroom and get injured.
He received a letter from the officer and he had noted that the flooring was far more than the minimum required for that purpose, he was disheartened that the officer seemed to be taking her side. I told him to read thru it again and see if a different meaning was applicable.
To me it was a simple factual statement that the flooring was far better (and more expensive) than it need be for the stated purpose but perhaps the officer was thinking do we really believe her stated intention?.
His intervention was after the children told him that one had indeed fallen off the ladder, thankfully not a great height so no harm done.
Apparently after changes were made after LA intervention the mother told her children that their father had stopped their fun of playing in it.
The point is though, the letter the father got could easily have been read to have one or the other meaning of "Job well done" or "Complete boulderdash!"
 
All my quotes for changing CU's come with warnings about unexpected issues and possible higher costs.

In this case the CU was changed so it makes perfect sense to get the installer back ......... this isn't about blame
Glad to hear it, good explanation, I am happy now you cleared it up.
 

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