Electric shower replacement

[P&Q]

Hi everyone,
I've got a customer wanting to replace an 7.5kW electric shower in their shower room, the cable is a 6mm twin and earth, approx. 10m long. Their main fuse box, is of the old rewire-able type, and the shower comes with an old, individual rewire-able shower unit. The customer has gone and bought a new RCD protected shower unit, and I wasn't sure whether just replacing the shower unit, would comply with the 17th edition.
By the way, there's no supplementary bonding present, and the gas & main earth cables are 6mm
I would appreciate your help guys, and thanks for your time in advance.

 

[DurhamSparky]

swapping the shower 1 for 1 is fine...
as for swapping the RCD unit thats different kettle of fish as it becomes notifiyable!! what set up is it TT or TN

what size are the main incoming L and N cables...??

if possible upgrade the earthing but if they look ok and show no signs of damage reuse them..!

 

[P&Q]

swapping the shower 1 for 1 is fine...
as for swapping the RCD unit thats different kettle of fish as it becomes notifiyable!! what set up is it TT or TN

what size are the main incoming L and N cables...??

if possible upgrade the earthing but if they look ok and show no signs of damage reuse them..!

Thanks for replying,
But can you replace a shower without adding RCD as the bathroom is a special location?
It's a TN, from the main supply to the meter the L & N are 25mm and from the meter to the main board they're 16mm with 6mm main earth, which are run along embedded in the wall for about 2m until they reach the main board in another room, hence upgrading the earth cables isn't going to be very easy.

 

[DurhamSparky]

interesting!! TN- bonding should be 10mm but as you have already stipulated you cant achieve it with out lots of mess..!!

Yes you can replace a shower with out an RCD as its classed as a replacement rather than new install or alteration.

my advice..!

Fit the RCD Unit to the supply remove the old wylex stuff and install your new shower..!

reconnect the 6mm gas and water and complete the job!

by doing that you have improved the safety of the circuit.

 

[P&Q]

interesting!! TN- bonding should be 10mm but as you have already stipulated you cant achieve it with out lots of mess..!!

Yes you can replace a shower with out an RCD as its classed as a replacement rather than new install or alteration.

my advice..!

Fit the RCD Unit to the supply remove the old wylex stuff and install your new shower..!

reconnect the 6mm gas and water and complete the job!

by doing that you have improved the safety of the circuit.

Thank you for all your advice,

 

[DurhamSparky]

oh and dont forget to inform LABC about your notifiyable work on the CU change!!

 

[nickblake]

Also do the supplimentary bonding in the bathroom as the lighting wont be RCD protected and also recommend an upgrade of the bonding appart from that as the top advice from duram

 

[P&Q]

Also do the supplimentary bonding in the bathroom as the lighting wont be RCD protected and also recommend an upgrade of the bonding appart from that as the top advice from duram

Thank you for your response, it's more geared towards my question, although as I said above, upgrading all the main earth bonding and supplementary bonding won't be easy, and this will be very expensive for the customer, and all he's after is replacing his shower unit. What would you say, would be the cheapest way to sort this out?

 

[SirKit Breaker]

If there is no RCD protection to the existing shower, then you cant replace it like for like. if you read the manufacturers instructions, it will state,"must be protected by an RCD" or similar.

Cheers..........Howard

 

[nickblake]

to omit the supplimentary bonding in the bathroom you could add the bathroom lighting circuit to the RCD unit for the shower , having said that to do this 100% then the main bonding will require upgrading ,

All you can do realy is Change the board to the RCD board , see if you can supplimentary bond the pipes in the bathroom and if possible the light to the shower cpc , test and make sure its ok with the RCD consumer unit as has been said will make the install safer
dont forget this work is also notifiable

make notes on the certificate what you have done and reccomend an upgrade of the earth 6 mm main bond isnt up to current standards but was in previouse editions so just make note of it on the cert

 

[P&Q]

swapping the shower 1 for 1 is fine...
as for swapping the RCD unit thats different kettle of fish as it becomes notifiyable!! what set up is it TT or TN

what size are the main incoming L and N cables...??

if possible upgrade the earthing but if they look ok and show no signs of damage reuse them..!

If there is no RCD protection to the existing shower, then you cant replace it like for like. if you read the manufacturers instructions, it will state,"must be protected by an RCD" or similar.

 

[Octopus]

If there is no RCD protection to the existing shower, then you cant replace it like for like. if you read the manufacturers instructions, it will state,"must be protected by an RCD" or similar.

Cheers..........Howard

Do the instructions for showers all say that?

 

[DurhamSparky]

i dont read them...!!! just look at power output and comissioning details...!!

it will only say protected by RCD to cover the manufactures ---!

 

[P&Q]

to omit the supplimentary bonding in the bathroom you could add the bathroom lighting circuit to the RCD unit for the shower , having said that to do this 100% then the main bonding will require upgrading ,

All you can do realy is Change the board to the RCD board , see if you can supplimentary bond the pipes in the bathroom and if possible the light to the shower cpc , test and make sure its ok with the RCD consumer unit as has been said will make the install safer
dont forget this work is also notifiable

make notes on the certificate what you have done and reccomend an upgrade of the earth 6 mm main bond isnt up to current standards but was in previouse editions so just make note of it on the cert

Thanks for your time, that was very useful info. It's all great and everything makes clear sense now.