Installing double oven temporary supply

[mrscalex]

Due to the nature of our kitchen re-fit I have to install some temporary cabling (in place for 2 or 3 weeks) from the supply for the double-oven. The supply itself is fine and reusable, I just have to move the cabling around. I have a few safety first questions.

1) Assuming I use a suitable junction box, is it okay to join cooker cabling (6mm or 10mm). I notice the DIY sheds don't stock them but my local shack has a beefy 60 Amp one.

2) Should cooker cabling be kept a certain distance from other services, eg hot water pipes and other mains cables?

2) Is it permissible to install the cooker control unit (and the terminal outlet plate) into a plastic surface mounted box? Or should these things always be in flush metal back boxes?

3) Is it permissible to have the cooker cabling surface clipped to the wall or temporary that it is, would it be better to put it in conduit?

And a real dibbo question. If a faceplate (of any type) has it's earth conection joined through to the ring earthing, why does there have to be a seperate back box to faceplate earth conection made too? Why do plastic surface mount boxes have an earth conenction but dry-lining boxes don't?

Many thanks. I have young children in the house and don't want to get this wrong.

Regards,

Robert

 

[ban-all-sheds]

1) Yes - make sure the connections are good'n'tight

2) Shouldn't touch or be too close to h/w pipes, but a few inches should be OK. Basically if you can't feel any heat radiating from the pipe, then neither will the cable. As for touching other cables, just the odd bit of contact is OK, bunching them together is not.

2) Surface is fine if you can find one to fit.

3) Clipped is fine, as long as it's not in a location where you think it needs special mechanical protection.

And a real dibbo question. If a faceplate (of any type) has it's earth conection joined through to the ring earthing, why does there have to be a seperate back box to faceplate earth conection made too?

Firstly, only metal faceplates have an earth connection. The metal box could become live under a fault condition, so it needs earthing too. The surest way to get a good faceplate earth connection is to use a flylead to the box. The regs do allow the faceplate to be earthed via the mounting screws provided one of the lugs is a fixed one, but most people prefer to do a proper job.

Why do plastic surface mount boxes have an earth conenction but dry-lining boxes don't?

Plastic boxes have one so that you can neatly terminate or join earths in cables when the accessory doesn't need an earth, e.g. light switches. It also gives you the ability to use a flylead to earth a metal faceplate, which is better because there is less chance of damaging the integrity of the earth circuit if you remove the switch for any reason, e.g. decorating.

The same requirements apply to dry-lining boxes - why they don't have earth terminals IHNI.

 

[mrscalex]

Well, what can I say but many thanks for such a prompt and comprehensive answer.

I just had a closer look at the gas hob ignition supply. It is supplied via an unswitched FCU from a spur on the main cooker supply. So it is switched on and off by the main cooker switch on the controller unit. It is even cabled with 10mm cable. Isn't this a bit OTT? Can I replace the supply with one fed via a switched FCU from the socket ring? The cooker and hub will be some way apart in the new kitchen.

Thanks,

Robert

 

[ban-all-sheds]

Well, what can I say but many thanks for such a prompt and comprehensive answer.

I'll give you my address - you can send money

I just had a closer look at the gas hob ignition supply. It is supplied via an unswitched FCU from a spur on the main cooker supply. So it is switched on and off by the main cooker switch on the controller unit. It is even cabled with 10mm cable. Isn't this a bit OTT?

No, as the protective device on the circuit is sized to protect 10mm² cable. If you were to use thinner stuff, and it got damaged, the MCB might not trip quickly enough to prevent problems. It is unlikely, but then so is a car crash, and you still have insurance...

Can I replace the supply with one fed via a switched FCU from the socket ring? The cooker and hub will be some way apart in the new kitchen.

Yup.

 

[mrscalex]

Many thanks again. The cooker was the only part of the cabling I was a bit hot under the collar about. I'm much happier now. Off we go...

Thanks,

Robert

 

[rightnwrong]

You can do it mrscalex. Good luck.

 

[ricicle]

You can do it mrscalex. Good luck.

I hope they have done it after 6 years !

 

[Adam_151]

Firstly, only metal faceplates have an earth connection. The metal box could become live under a fault condition, so it needs earthing too. The surest way to get a good faceplate earth connection is to use a flylead to the box. The regs do allow the faceplate to be earthed via the mounting screws provided one of the lugs is a fixed one, but most people prefer to do a proper job.

No, its the reverse they allow, a metal K/O box flushed in a wall is allowed to be earth via a fixed lug, but not vice versa, i.e. If you have a metal switchplate on a K/O box, the cpc muct be connected to the switchplate not the box if there is no flylead present.

Can't remember the reg no off hand, but IIRC its a little hidden away as it starts off about wiring systems such as MI, SWA which inheratly connect cpc to the enclosure and the need to install the flylead because of this

I trust this was just a simple wording error bas.... [/b]

Edit: I seem to have been caught out by a prehistoric post which has perculated to the top....

 

[Adam_151]

Firstly, only metal faceplates have an earth connection. The metal box could become live under a fault condition, so it needs earthing too. The surest way to get a good faceplate earth connection is to use a flylead to the box. The regs do allow the faceplate to be earthed via the mounting screws provided one of the lugs is a fixed one, but most people prefer to do a proper job.

No, its the reverse they allow, a metal K/O box flushed in a wall is allowed to be earth via a fixed lug, but not vice versa, i.e. If you have a metal switchplate on a K/O box, the cpc muct be connected to the switchplate not the box if there is no flylead present.

Can't remember the reg no off hand, but IIRC its a little hidden away as it starts off about wiring systems such as MI, SWA which inheratly connect cpc to the enclosure and the need to install the flylead because of this

I trust this was just a simple wording error bas.... [/b]

Edit: I seem to have been caught out by a prehistoric post which has perculated to the top....

Edit2: What on earth has happened here?!!

 

[MalcofArabia]

Think you got sucked into an american time warp, though I read it as well lol

In fact I was interested in what reg it was as well as the only thing I know in the BRB about flyleads on a back box is 543.2.7 and that is if your using conduit, trunking etc as the CPC.

Sure someone will point in the right direction