Electric shower

[ryan24]

Hi all,

i am am looking at installing an electric shower in my property. The problem is it is an old 4way wylex consumer unit with no rcd or spare ways. All the circuits fed of the cu are run in old imperial conduit with no cpcs. The conduit is used as the cpc. Will it be ok to just replace the consumer unit and add the shower to this. If I use rcbos for all the existing circuits will they still be ok just using the conduit as cpc? Also if I use rcbos will I still need bonding in the bathroom as all pipework is copper? The main fuse is 60a is it ok add 10kw shower to the new board? Thanks in advance everyone

 

[Octopus]

I would consider splitting the tails, adding a 2nd board and upgrading the bonding.

Changing a CU where the conduit connects to the old metal CU is a pain in the ---!

 

[7029 dave]

I would agree, second DB.

 

[ryan24]

Hi thanks for your response. I forgot to say actually that the conduit is all terminated into an adaptable box behind the cu. it doesn't connect to the board itself.

 

[davesparks]

Whilst a second cu to feed the shower is a possibilty I would first look at the possible benefits of replacing the existing one with a larger one. Replacing a board with conduits connected to it isn't particularly difficult, you just have to make sure you have good electrical contact with the conduit (same as any conduit work)

Either way the main bonding and any requirement for supplementary bonding will need looking at.

 

[telectrix]

if you can be sure that the conduit is earthed, then do your CU swap. ask DNO for a fuse upgrade to 80A. ( make sure you remove the by-pass first ). lol.

 

[davesparks]

Or just leave the fuse as it is, that won't mind having a 10KW shower on it. You'd have to add ~4.5KW to even get to it's rated value, let alone anywhere near actually operating

 

[Guest77]

Agree with Murdoch entirely, this way you don't have to worry about existing circuits being up to scratch either, just deal with the bonding and you only have to worry about the shower. As the installation is that old changing the existing board to a larger one is suicide IMO.

 

[davesparks]

In what way is it suicide?

I would worry about existing circuits being up to scratch before adding anything new.

He is talking about his own property so there is not the problem of quoting against someone who will bash it in for a couple of pints.

I would think the sensible advice is to take the opportunity to at least get the existing installation inspected and tested and find out what is there.

 

[Guest77]

Because a simple shower job could end up a full rewire if the existing circuits were in a mess if you were to change the whole board, or if you changed the board and the customer refused to have a rewire and the existing circuits were indeed in a right mess you would have to either leave the house with dangerous circuits after replacing the board or put the circuits right at your own cost, I can imagine the judge now, mr davesparks the customer only wanted a shower putting in, you conned him into a new board change then wanted another 3k to rewire the house, when he refused you left his home with some circuits not working due to the RCD not staying in and the property was in a worse state after you left, 10 years no parole lol

 

[Octopus]

Well.....I would discuss the 2 options with the client and then send him/her 2 estimates - then sit back while they decide!

 

[Guest77]

In what way is it suicide?

I would worry about existing circuits being up to scratch before adding anything new.

He is talking about his own property so there is not the problem of quoting against someone who will bash it in for a couple of pints.

I would think the sensible advice is to take the opportunity to at least get the existing installation inspected and tested and find out what is there.

Agree with that

 

[7029 dave]

deleted

 

[dingledong]

Me .I'd go for a new board

 

[Clive P]

Hi,
It's his own property so I would go with Dave and Ding on this one. Upgrade and sort everything out in a oner.

Regards.

 

[davesparks]

Because a simple shower job could end up a full rewire if the existing circuits were in a mess if you were to change the whole board, or if you changed the board and the customer refused to have a rewire and the existing circuits were indeed in a right mess you would have to either leave the house with dangerous circuits after replacing the board or put the circuits right at your own cost, I can imagine the judge now, mr davesparks the customer only wanted a shower putting in, you conned him into a new board change then wanted another 3k to rewire the house, when he refused you left his home with some circuits not working due to the RCD not staying in and the property was in a worse state after you left, 10 years no parole lol

Well.....I would discuss the 2 options with the client and then send him/her 2 estimates - then sit back while they decide!

He said in the OP that it is his own property, don't think there's much discussing with clients or sending of quotes to do here!

 

[Guest77]

Aye very true I got off topic and apologise Dave, saying that all is fine unless he wants to sell the place then a can of worms could be opened.

 

[ryan24]

Thanks for your help everyone. I'm still thinking of going down the route of replacing the db. It only has 4 circuits. 1 for ring main, 1 for lighting, 1 for cooker and 1 for the doorbell. It is a 2 bed flat. As long as i do continuity checks on the conduit I'm hoping everything should be fine. Also the existing 60a main fuse should be fine shoudnt it? Thanks again

 

[davesparks]

You need more than continuity checks, you need to carry out all of the standard tests using the correct test equipment.
A continuity test with a standard multimeter is not the same as with a proper calibrated tester (mft or seperates)

 

[davesparks]

And I can see no issue with a 60A fuse

 

[malcolmsanford]

If the conduits are terminated into an adaptable box does your existing board pick up the earth OK?

 

[7029 dave]

If the conduits are terminated into an adaptable box does your existing board pick up the earth OK?

Probably lugs of AB.lol Conduit's must enter metal clad DB from AB surely.!!?

 

[HappyHippyDad]

Thanks for your help everyone. I'm still thinking of going down the route of replacing the db. It only has 4 circuits. 1 for ring main, 1 for lighting, 1 for cooker and 1 for the doorbell. It is a 2 bed flat. As long as i do continuity checks on the conduit I'm hoping everything should be fine. Also the existing 60a main fuse should be fine shoudnt it? Thanks again

If the door bell has its own circuit and the MCB is not feeding anything else then you could pop the door bell in with the lights and then you've got a spare way. Replace with a 40A fuse or Wylex plug in MCB and then take to a standalone RCD. That would save you alot of hassle with the CU change!

 

[davesparks]

If the door bell has its own circuit and the MCB is not feeding anything else then you could pop the door bell in with the lights and then you've got a spare way. Replace with a 40A fuse or Wylex plug in MCB and then take to a standalone RCD. That would save you alot of hassle with the CU change!

The ways in those Wylex boards are normally only designed for 30A each, if you wanted a higher load they used to do a board with a seperate 'higher load' way, often mounted on the other side of the main switch.

 

[telectrix]

rip it all out and fit one of these. plenty spare ways then. just need DNO to bung in a 3 live thingy cable.



and before anyone else spots it... yes the grey and black of the SWA ( cpc and N ) are crossed,this was picked up on initial checks before powering up.