Can you get a cooker switch with integrated RCD?!

[ed-ectrician]

I'm putting in a new cooker for some friends. I am part P registered and have done 2330 level 2 and 3 and 17th ed. by the way! It's a cannon harrogate 60cm cooker - looks like 4.5kw so draws 19.6 amps at 230 volts (where have you ever seen 230 volts anywhere in the uk it is always 240?!)- Cannon, HARROGATE, Free-Standing Cooker | Appliance House

Firstly - as it's gas hob so less wattage am i right in thinking i could use 2.5mm T+E for this and put it on a 20 amp breaker? 2.5mm T+E can take (ref method C) 27 amps so this is ok taking correction factors into consideration. I am going to put it on its own circuit and use a retrofit 20amp wylex MCB. It is an old rewireable board. Will this be ok or trip out as it is quite near the mcb's capacity - I know MCBs trip a fair bit higher than their rating but wanted to double check.

Secondly - this circuit (and the whole bloody house!) needs an RCD as it is not more than 50mm in the wall or armoured etc etc etc. Can you get a cooker control switch that has an integrated RCD in it? I am struggling to find one! They don't want a board change - just this cooker doing but I am duty bound to put an RCD on this circuit or i could get in hot water!

Thanks a lot all.

Ed

 

[ed-ectrician]

PS - I dont like applying diversity to cookers as i dont want it to go ---- up on xmas day! Also it seems fairly easy and cheap to get this one installed without diversity as it is a smaller load than all electric cooker.!

 

[ashrow]

RCD at the origin of supply for the circuit you alter, just put a RCD after the DB for that circuit if needed and also check the main equipotential bonding to services etc and upgrade if needed

Will leave the calcs for you to work out (but i always run a 6 mm minimum incase the cooker is changed later on)

 

[colshaws]

Are you talking about installing new circuit back to the board, if so if this is going in the wall less than 50mm etc then the RCD will need to be at the board to protect the circuit.

 

[ed-ectrician]

Good point colshaws and Ashrow - It's an old rewireable wylex board - how do i get an rcd at the board?! Can you get retrofit RCBOs?!

 

[RyanCheetham]

Use a stand alone rcd unit just outside the consumer unit

 

[ed-ectrician]

ps - so i'll use 6mm cable on a 40 amp mcb...

 

[colshaws]

Dont think you can get RCBO for the old board, there was a similar post a while back. Come off the rewirable spare way to a small garage/shower rcd cu and onto your cooker circuit and as Ashrow said dont forget to check bonding etc

 

[valleybilly]

Providing the cable you fit is surface mounted you don't need rcd protection ,

 

[ashrow]

ps - so i'll use 6mm cable on a 40 amp mcb...

Even with a short run i never use 6 mm T&E for 40 amps but that just me !
If you are going to install a new circuit for the cooker then YOU need to do the clacs and install as per regs
I would also upgrade the main equipotential bonding to current regs regardless if the existing 6mm (in my opinion undersized) calculates as suitable on the house supply
If the client does not want a consumer unit change i either come from the exisitng BD to a rcd then to the circuit but more often then not i split the tails to a new rcd 2 or 3 way consumer unit and then run the new circuit and then have a few spares for later use

 

[telectrix]

yeah. RCD is only needed if cable is buried in wall < 50mm deep. as for cable, i'd use 6mm on a 32A MCB. this will allow for a larger cooker in the future,

 

[ed-ectrician]

Of course, clipped direct dont need an rcd. Thanks

 

[ed-ectrician]

What does club3000 mean?!

 

[vjsmarwick]

If your cooker only draws 19A even if fitting a 6.0 mm incase of future change of cooker I would still fuse it at 20A to give you better compliance for regs and better protection for the cooker too or at a push 32A but never as much as 40A but again that's just me too. Lol.

 

[Amp David]

What does club3000 mean?!

HAHA, make another 2893 posts and you'll find out!