New Shower cable thickness advice and max shower watts

Hi lads

Thanks for replies

Got one more question though, phoned a local electrician that hopefully should be coming round to price and check up house on Friday he first asked if the house was bonded pipe work and gas all to do with the P i said i think so as there are cables linked in certain places is this what bonding is (see pics.)

The main box has thick earthing cable to it like this


Linked like this


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The earthing arrangement shown in your picture is NOT the main Earth bonding.
The Gas & water mains entering your premises should be bonded back to the MET (Main Earth Terminal) within 600mm of entry to the building.
Find your gas meter and water stop cock and check in those areas for the main bonding.
Should be 10mm2 green/yellow cable.
Ok thanks for the info

Is this correct then


The one end under near stop tap comes out of wall but does not connect to anything its got end fitting on looks like its been forgot or something ive rested it on pipes intill friday.


But there are other earthing cables to other pipes.
The bond to the gas looks fine to me.
The water is difficult to tell, there appears to be an earth clamp on one of the pipes but, I can't see if one of the earth wires is connected to it.
It should be the same size as the gas one.
It is possible that the "loose" wire you have found was an old undersized earth cable that has since been replaced with a larger one.
can you confirm?
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Fuseblower, don't forget, not all supplies require 10mm2 protective bonding conductors, for example, 6mm may well be adequate for a TN-S supply.
However, to be sure that 6mm² is sufficient, you need to do some calcs.

If you use 10 on TN-S, there's no need to worry about calcs.

6 is OK for PEB's on TT.

Some DNO's insist on 16 for TN-C-S.
However, to be sure that 6mm² is sufficient, you need to do some calcs.

Hence the 'may well be adequate' bit - subject to working via the adiabatic equation.
I wonder how many PIR's bring up undersized PEB's on a TN-S supply when 6mm exists?
As to your shower I look at Yellow crimps and I would think looking at that you have 6mm sq cable. If PVC and not in insulated wall then 34 amp max i.e. 7.8kW with 4mm 27 amp or 6.2kW so would think 6mm there is a thermosetting cable which is higher ratted but normally white sheave. As to water earths there are plastic pipes so may not be required to same extent. Hard to tell with pictures but other than the consumer unit change which you say is already arranged seems no real faults but it is up to the guy who signs the paperwork and no real good asking here it is what the guy on the job says that goes.
Looking at the picture

The left is were the thickest cable disapears into wall (same thicknes as Gas cableing) it goes to the bracket fixture shown then splits of to a thinner cable that disapears if i remember right was connected to the tumble dryer the previeus home owners had in place.

Im sure this is probably the start of the bonding that leads to the main box but might have been left unconnected off when they disconnected things when they moved maybe.

The cable at the bottom is bridging passed the water meter.

Is it ok to buy a bracket and connect it to one of the water pipes for now?


Thanks so much for your info so far.
Thanks for the explanation, It's a bit clearer now, Looks like the earth bonding clamp has been taken off the water pipe for whatever reason.
As you suggest, purchase a new earth clamp and re establish the connection on your side of the meter.

However, to be sure that 6mm² is sufficient, you need to do some calcs.

If you use 10 on TN-S, there's no need to worry about calcs.

6 is OK for PEB's on TT.

Some DNO's insist on 16 for TN-C-S.

OK Glad you pointed that out, But I note from the top picture of this thread that the OP's system is marked PME.
Hi lads,

Just to update the local electrician came round to look at CU and said the Earthing is fine and shower is 6MM cable ;)

Just waiting on quote from them for the new CU

Thanks very much for all your info it was much appriciated


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