shower installation

[spex]

Afternoon guys, i am just looking for abit of advice...
i am fitting an 8.5kw shower, the installation is a TT system, the consumer unit has a 63a 30ma rcd covering all circuits as the main switch, it has 16mm tails, what i am thinking of doing is splitting the tails using a henley block with 16mm tails to the new 2 way rcd unit that i am going to fit with a 63a 30ma rcd and a 40a circuit breaker, i am wiring in 10mm twin and earth. the original consumer unit is not labelled correctly, when im asked on the installation certificate about comments of installation do i write nothing because i am not using the original consumer unit?

 

[mark80]

Certificate only applies to the work you are carrying out so even if you add to the existing DB it's fine aslong as your work complies. You still have to make sure bonding is all ok either way and if you notice anything wrong with the installation you should note it down on the sheet but it is not your responsibility to fix.

 

[spex]

Certificate only applies to the work you are carrying out so even if you add to the existing DB it's fine aslong as your work complies. You still have to make sure bonding is all ok either way and if you notice anything wrong with the installation you should note it down on the sheet but it is not your responsibility to fix.

Hi mike, thanks for your reply, there is spare ways in the board, so am i ok to just jump straight into that then with a 40a mcb? maybe i have been going into it too much!

 

[Octopus]

Add to the existing CU makes much more sense and make sure that when you write up your EIC the "description" of works specifically covers your work only.

 

[GLENNSPARK]

Add to the existing CU makes much more sense and make sure that when you write up your EIC the "description" of works specifically covers your work only.

hold on....he`s only got 63A to play with on the existing CU.....up the RCD to 80A....or put an add on board for shower....
make sure tails etc are up for extra load....

 

[Octopus]

hold on....he`s only got 63A to play with on the existing CU.....up the RCD to 80A....or put an add on board for shower....
make sure tails etc are up for extra load....

Fair point, bit of a pain if the misses is cooking dinner and you're having a shower and all the power goes off!

 

[DieselShunter]

What's the company cutout rated?

If it's 60A then there's no need to uprate the RCD.

 

[mark80]

Its your call really on what you do. If the customer is happy to pay for the additional CU then go ahead and fit it! With people saying about it tripping with excessive load, I doubt you will have a problem with this as the shower or cooker will not pull the full load current and correct me if im wrong, but surely the RCD will not trip at exactly 63a?? Its got to allow for short period overloads surely like an MCB?
I see loadsss of 16th edition Crabtree starbreaker boards and these are fitted with a single 63a RCD which has atleast the cooker, shower and socket circuits on it and I've never heard of any problem of these tripping. If everyone thought like that then we'd be needing 3 phase supplies to domestic properties haha!!!!

 

[DPG]

Surely the 63A RCD rating is the maximum permitted current through it, rather than a value at which it 'trips'. Daz

 

[monkeyelectric]

Its your call really on what you do. If the customer is happy to pay for the additional CU then go ahead and fit it! With people saying about it tripping with excessive load, I doubt you will have a problem with this as the shower or cooker will not pull the full load current and correct me if im wrong, but surely the RCD will not trip at exactly 63a?? Its got to allow for short period overloads surely like an MCB?
I see loadsss of 16th edition Crabtree starbreaker boards and these are fitted with a single 63a RCD which has atleast the cooker, shower and socket circuits on it and I've never heard of any problem of these tripping. If everyone thought like that then we'd be needing 3 phase supplies to domestic properties haha!!!!

An rcd is not overcurrent protection only fault current so it won't trip unless theres a fault

 

[mark80]

Cheers for that, wasnt sure whether it was or not! Personally, off that advice then id fit a seperate DB for the shower

 

[spex]

the service cut out is 60a, so if i put a 2way rcd unit in with a 63a rcd and a 40a breaker, would i just upgrade original tails to 25mm and add 25mm tails to my new DB? the reason im going into it so much is because i am putting this job forward for my periodic assessment with the n.i.c so obviously i want to get it spot on!.......thanks for the comments guys.

 

[monkeyelectric]

the service cut out is 60a, so if i put a 2way rcd unit in with a 63a rcd and a 40a breaker, would i just upgrade original tails to 25mm and add 25mm tails to my new DB? the reason im going into it so much is because i am putting this job forward for my periodic assessment with the n.i.c so obviously i want to get it spot on!.......thanks for the comments guys.

I think 25mm would be a bit ott, its only a shower and its a 60a cutout, would you not want it spot on if it was'nt your nic assessment?

 

[spex]

every job has to be spot on, just the added pressure of the assessment!

 

[monkeyelectric]

every job has to be spot on, just the added pressure of the assessment!

I know i was only messing:biggrin5:, i'm very particular about doing everything correctly and the one job i forgot to put a mixed colour warning on i used for my assessment, he was ok and just told me to get one off the van whilst we were there

 

[SirKit Breaker]

hold on....he`s only got 63A to play with on the existing CU.....up the RCD to 80A....or put an add on board for shower....
make sure tails etc are up for extra load....

He wont have a problem, the shower wont be on long enough for it to blow the fuse, unless he leaves it running for a fortnight when he goes away on holiday.

I have fit loads of showers with an assumed 60a main cutout fuse, i say assumed, because we dont remove them do we:smilewinkgrin: to find out. His shower is only going to pull 36 amps assuming it is on maximum hot, diversity and so on, he will be fine.

my concern is the Part P thing.

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

 

[Edd]

Im just replying so I get a fank you ohhh yere as they say above

 

[spex]

Hi what concern do you have about the part p thing ?