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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> Wire an integrated oven https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1375907599 Message started by lobsters on Aug 7^th, 2013, 9:33pm

Title: Wire an integrated oven
Post by lobsters on Aug 7^th, 2013, 9:33pm

Hello chaps,

I am installing a new electric oven and gas hob into my kitchen and I have a couple of questions.

1. The oven in question is a Bosch HBA13B150B rated at 2.9 KW with an IEC inlet. The documentation doesn't contain any power specs but according to the supplier (appliances direct) they say it requires a 16 A supply.

However, in the U.K. 2.9 KW is a draw of 12.06 amps. The previous slot in cooker was fed from a 13 amp FCU flex outlet with a 2.5mm TRS trailing lead. Can I feed this new oven from that feed or do I need to upgrade?

2. The new hob requires a supply for the igniter which I have spurred up a 3 amp FCU from the oven FCU in 6mm, which is fed from the cooker isolator on the kitchen wall.

I would like to take another spur up to feed a 3 amp FCU feeding a cooker hood and keep it all on the same isolator, again, fed with 6mm.

Is this ok? It will be electrically sound but I'm not sure how compliant to regs it would be.

A bit about myself. I trained as spark many years ago (16th edition) and for twenty years have been a lighting technician in theatre and music. I work with electricity every day and consider myself competent and confident with electricity. However, it has been a good while since I did anything domestic so I'm unsure of common practice in that area these days.

Many thanks in advance.

Steve

Title: Re: Wire an integrated oven
Post by Lectrician on Aug 8^th, 2013, 9:19pm

Nothing wrong with anything you suggest, although it is usual for the hood to be fed via the ring final circuit.

The 6mm spurs maybe a tad OTT - 4mm would be ample, protected against both fault current and overload.

Title: Re: Wire an integrated oven
Post by lobsters on Aug 25^th, 2013, 6:02pm

Thanks for the reply. I'm using 6mm as the existing feed is 6mm, and I don't mind a bit of over-engineering.

I've decide to try the existing 13a feed. The worst that can happen is the fuse runs hot and keeps blowing. If it does I'll do a more extensive wiring change. The cooker hood I will take via an FCU off the ring main. If I do need to upgrade it'll be less hassle in the long run.

Any tips on running a cable behind a stud wall without demolishing it? The feeding socket is 1m off the floor, I would be running 50cm sideways from it then 1m upwards.

Title: Re: Wire an integrated oven
Post by CWatters on Aug 30^th, 2013, 12:06pm

The spec on the Bosch web site mentions 16A but not 2.9kW (at least not that I can see). Is that from the rating plate?

The installation instructions mention versions supplied with either a cable or a lead fitted with a plug. Was a lead with IEC plug supplied?

They also say "Do not connect using a 13A plug or protect with a 13A fuse".

Hope this link works...

http://goo.gl/O8w96Z

Heating elements draw more current when cold so it's possible the 2.9kW rating is with the element hot and the 16A rating is to cover the max surge when the cold element switches on.

Title: Re: Wire an integrated oven
Post by lobsters on Aug 31^st, 2013, 1:02am

CWatters wrote on Aug 30^th, 2013, 12:06pm:

Heating elements draw more current when cold so it's possible the 2.9kW rating is with the element hot and the 16A rating is to cover the max surge when the cold element switches on.

Interesting, I did not know that. Makes sense though.

The 2.9Kw rating is from the backplate and the listed spec. The cable supplied is a bare ends to IEC. I have run the oven for a couple of hours with no fuse failure. Not that that proves anything. I guess I'll need to change the set-up.

In which case, can I get a 16A FCU? I regularly use 16A MCB outlets in theatres. They are rather clunky boxes though.

If I can't get a 16A protected outlet am I looking at dropping down to a 16 A MCB on the consumer unit and changing the cooker control unit to one without the 13A socket?

Thanks for the reply

Steve

Title: Re: Wire an integrated oven
Post by CWatters on Sep 1^st, 2013, 8:50pm

My background is in electronics, I'm not an Electrician so can't really comment on the regs...

I don't think you can get a 16A FCU. I don't think 16A fuses are available to fit one? I might be wrong though.

Title: Re: Wire an integrated oven
Post by woodsmith on Sep 2^nd, 2013, 7:28am

This is the problem with 16A appliances, I rarely see them fitted correctly as they are usually run off a 30A breaker that was fitted for the previous oven. For my kitchen I fitted a small consumer unit in one of the cupboards, fed by a 30A breaker, and fitted two 16A breakers, one for the oven and one for the domino hob.

Title: Re: Wire an integrated oven
Post by londonman on Oct 3^rd, 2013, 5:09pm

woodsmith wrote on Sep 2^nd, 2013, 7:28am:

.... and one for the domino hob.

Is that the new Festool cooker ? ;)

Title: Re: Wire an integrated oven
Post by TIMBA-WOLF on Oct 3^rd, 2013, 9:29pm

londonman wrote on Oct 3^rd, 2013, 5:09pm:

woodsmith wrote on Sep 2^nd, 2013, 7:28am:

.... and one for the domino hob.

Is that the new Festool cooker ? ;)

:) close, but easy to "SPOT" the difference... (it's a two unit/ring hob...) :)