Sparky advice.

[Milzy]

I’m getting two new ovens in a new kitchen in a few weeks. Cables probably 10mm need to run a short distance through the roof from the main consumer unit board.
The worry is my consumer unit is made out of plastic and is about 17 years old. I’ve heard new regs mean you should have a metal box now?
Do I need a new box for the electrician to sign off my hob & oven?

 

[Deleted member 26715]

I don't think there is anything that says you must for existing CU's but new instals I believe have to be metal, but as this will fall under Part P minimum ask the person who is going to sign it off.

Although all this Part P, NICC & the rest of them as just a con

 

[jowwy]

I’m getting two new ovens in a new kitchen in a few weeks. Cables probably 10mm need to run a short distance through the roof from the main consumer unit board.
The worry is my consumer unit is made out of plastic and is about 17 years old. I’ve heard new regs mean you should have a metal box now?
Do I need a new box for the electrician to sign off my hob & oven?

If im not mistaken, doesnt it need to be metal if placed near an exit to the property???

Also if people have to do retrofits every time a new reg came out, then no house would be valid

 

[Cycleops]

I should be led by your electrician, he'll know what the standard required is now.

 

[si_c]

Unless there is insufficient space in the CU then they won't change it, the regs apply to new installations, re-wires or replacements where unsafe. An existing CU is covered by the regs in place at the time of installation.

This is why you can have the old CUs with wired fuses still in place in older buildings. The exception to this is I believe for certain appliances such as EVs which may require a particular breaker type in which case the CU may need replacing, although I'm not a electrician so take that with a huge dose of salt.

 

[slowmotion]

I should be led by your electrician, he'll know what the standard required is now.

Ahem. Let me fix that for you.....

......." he'll know how to fool you into spending a lot more money by giving bogus advice about The Regs."

 

[Milzy]

I’m getting an EV charger in next year so may need to re do the mains wires anyway. A sparky I used to work with said if it was him he’d keep the old plastic box. The metal box reg is supposed to stop firemen breathing plastic fumes in. They already have air masks on & theres other plastics burning besides. Joke man.

 

[I like Skol]

Looks like you have the same/similar consumer unit as me (installed in 2012-13 as part of a property extension project) and you appear to have two spare slots that would take a couple of 16A breakers to feed your ovens.

Not familiar with regulations, but can't see any practical reason why your existing CU won't be adequate for the cooker upgrade.

 

[Lozz360]

You will probably need a bit more than 16A supplies for ovens. I guess you already knew that as you mentioned 10mm cables. It’s correct that you won’t need to replace the CU just because it is plastic. It’s new installs that need to be metal. You have two spare ways at 7 & 8, so you should be OK for the two additions. You already have a supply marked “cooker”. Does this mean you will have three ovens installed? Is this a dwelling or a cafe? Just curious.

 

[I like Skol]

I would be surprised if the individual ovens suck more than can be supplied by a 16A breaker. I stand to be corrected.

 

[Lozz360]

You are correct in that if they are just ovens with no hobs then 16A should suffice. But when people refer to an oven they mean an oven combined with a hob. Or at least that’s what I pictured.

 

[si_c]

Also depends on the size of the ovens, a double oven might need a 32A or 50A breaker.

 

[lazybloke]

I think a decent induction hob draws more like 40 amps.

My dual electric oven range thing only draws 13 amps, and has a standard plug.
Edit: it has a gas hob , otherwise it would draw more current.

 

[cosmicbike]

Standard ovens are 13A or less. Good practice for ovens is a fixed supply via fused connection units (fused spurs), switched or unswitched your choice. For me I'd be having a single 10mm feed from a 32A breaker, split out behind the ovens into a pair of FCU's fused at 13A each, one for each oven.
Any electrician installing a single new circuit into an existing installation is responsible for that circuit only. They may have a view on your current DB being 'non-compliant' with latest Regs (18th Edition), but cannot make you replace it.
If you are getting an EV install next year then I would ask your electrician to check your head fuse, if it's 80A you are pushing your luck even with diversity, so you may need to have a natter with your DNO for a 100A upgrade.

 

[fossyant]

Ah, the cheeky buggers buying MIL's house have said the CU isn't up to current specs - it won't be, as was put in over 20 years ago - hmm trying to get us to cough up for a new one.