Cooker diversity calculations

[Pete_Gillson]

Could someone please just giving me the nod that I'm not nuts!

Simple cooker swap big range induction beast with max draw of 16.2Kw

With a socket I make it 33Amp.

Imagine my confusion when customers shows me all the materials he has for the job which a spark has charged £500 for but no longer answers the phone. Big reel of 10mm swa, metal outdoor enclosures, industrial outdoor isolator, etc.

Dubious about this guys intentions!

 

[Wilko]

Hi - I'd rather consult manufacturers instructions, hopefully they will be sensible ?

 

[Richard Burns]

Well the 10mm² is probably correct not sure about the cable run for the cooker unless it was previously on 6mm² and they were trying to get a new external cable route to the cooker?
I still cannot see where the isolator comes in surely you would want a cooker switch inside the kitchen.

 

[Pete_Gillson]

I get if it was all new and needed replacing I'd install 10mm but there's a decent 6mm available.

Apparently he wanted to dig a trench then changed his mind and said he'd just run it through the loft with the old one. It's quite a long run maybe 15m but it's mostly clipped direct, no significant insulation.

I'm trying to give him the benefit of the doubt but me thinks he's just a chancer. I don't buy much industrial gear but I can't imagine 30m of cable and some switch gear coming to £500.

 

[westward10]

What size/make is the switchgear, the best brands can set you back a fair sum.

 

[Pete_Gillson]

It was just a big empty metal box, 45amp (?) 1/4 turn switch, something in a contactum box. My only thought was maybe planning on a contactor outside kitchen with a switch inside but that's a lot of effort for a cooker!

 

[Octopus]

Big reel of 10mm swa, metal outdoor enclosures, industrial outdoor isolator, etc.

Dubious about this guys intentions!

I suspect the customer bought the bits himself ...

What make of cooker is it?

 

[Pete_Gillson]

No, cable had electricians delivery address on it

It's a rangemaster 110 don't have the model number at hand. I read their installation PDF and there wasn't anything specific just use correct cable and max size for terminals 100mm

 

[Midwest]

The Rangemaster web site suggests 14.5kW and 45amp 'cookerbox'.

I make that 30.9 amps (with socket)

 

[mattg4321]

28.1 Amps or 33.1 Amps with a socket outlet (assuming 16.2Kw)

Use existing 6mm on 32A MCB and fit 45A DP switch without socket. Amount of idiots who don't use diversity when considering cooking appliances is staggering.

 

[stevethesparks]

Its never going to draw 16.2 KW.
For that make, I may be wrong, but not all ovens/grill can be on at the same time. As regards the hob, only one ring can have boost activated, if you boost another ring the other reverts back to its original power setting. Along with cycling and the unlikely case that all will be on at once (not a commercial kitchen). If you could swap the switch to one without a socket I'd bet you'd have no problems supplying this on a 32 Amp breaker. Dependant on length of run and install method the existing 6.00 will probably suffice.
Then again, as you have most of the gear you need to upgrade, then why not.

 

[Pete_Gillson]

Thanks everyone, good point about swapping the cooker plate to remove socket. It's been running fine on a 32a MCB for a few days, just wanted to rest my mind.

I appreciate forgetting diversity, I suspect it wasn't an accident though. Same guy told another one of my customers they need a board change because a breaker kept tripping!

Also now I'm on a rant they say on their website they're registered with NIC & Elecsa

 

[Octopus]

No, cable had electricians delivery address on it

It's a rangemaster 110 don't have the model number at hand. I read their installation PDF and there wasn't anything specific just use correct cable and max size for terminals 100mm

Right.... We have a range master 90 with a max wattage of 17.7 kw. The range master info for ours stated 6mm minimum

 

[snowhead]

Also now I'm on a rant they say on their website they're registered with NIC & Elecsa

I wouldn't waste anymore time thinking about the other Guy.
Just do whatever you would have done if you'd got there first.
If use need to use any of the materials they're there.