In article ,
antgel writes:
Hi all,

Thanks to all your help, I've finished the lighting in my lounge and
kitchen, and everything works well.

I'm moving onto the kitchen electrics now. I'm buying a built-in oven
and a built-in microwave, both of which have plugs on. Is it okay to
run an unswitched double socket from the cooker switch? I'm sure that
the microwave would work on the normal ring, but for convenience I'd
like to plug it into the cooker circuit this way.

Providing there's no wired-in cooker on it anymore, then yes,
you can effectively turn it into a 20A or 30A radial circuit.
If the circuit is protected at more than 30A (fuse or MCB),
then reduce the protection to 30A max.

Also, am I allowed to wire a hob from another unswitched socket wired
from the cooker switch? I suppose this would be like having two spurs
from the one switch which I know is not allowed on rings, but I'm not
sure about radials. It would be fantastic to be able to switch all
three appliances on and off via the single switch.

Yes, that's fine too.

--
Andrew Gabriel

Andrew Gabriel wrote:
In article ,
antgel writes:
Hi all,

Thanks to all your help, I've finished the lighting in my lounge and
kitchen, and everything works well.

I'm moving onto the kitchen electrics now. I'm buying a built-in oven
and a built-in microwave, both of which have plugs on. Is it okay to
run an unswitched double socket from the cooker switch? I'm sure that
the microwave would work on the normal ring, but for convenience I'd
like to plug it into the cooker circuit this way.

Providing there's no wired-in cooker on it anymore, then yes,
you can effectively turn it into a 20A or 30A radial circuit.
If the circuit is protected at more than 30A (fuse or MCB),
then reduce the protection to 30A max.

The current MCB for the cooker circuit is 15A. Is this likely to be
enough to power an oven, microwave, and hob? I can't uprate it as my
CU can only take 100A max. If it's going to be a problem, I suppose
I'll have to have to put the microwave and hob on the normal ring.

Antony

In article . com,
"antgel" writes:


Andrew Gabriel wrote:
In article ,
antgel writes:
Hi all,

Thanks to all your help, I've finished the lighting in my lounge and
kitchen, and everything works well.

I'm moving onto the kitchen electrics now. I'm buying a built-in oven
and a built-in microwave, both of which have plugs on. Is it okay to
run an unswitched double socket from the cooker switch? I'm sure that
the microwave would work on the normal ring, but for convenience I'd
like to plug it into the cooker circuit this way.

Providing there's no wired-in cooker on it anymore, then yes,
you can effectively turn it into a 20A or 30A radial circuit.
If the circuit is protected at more than 30A (fuse or MCB),
then reduce the protection to 30A max.

The current MCB for the cooker circuit is 15A. Is this likely to be
enough to power an oven, microwave, and hob? I can't uprate it as my
CU can only take 100A max. If it's going to be a problem, I suppose
I'll have to have to put the microwave and hob on the normal ring.

Add up the power ratings of the appliances. (I'm assuming the Hob
is just a spark ignitor on a gas hob, and not an electric hob.)
If the power rating totals more than 3450W, then 15A isn't enough.

BTW, the 100A max on the CU is the max current load, not the max
total of all the breakers. There are a set of diversity guidelines
in the IEE On-Site Guide which give guidance on how much the total
MCB ratings can exceed the 100A value, given that many circuits
are unlikely to be operating at max load all the time.

Also, before uprating the fuse, you will need to check the circuit
is still properly protected by a higher current fuse. This would
be governed by the size of cable conductors, the length of the
cable run, and if the cable passes through any thermal insulation
or warm areas.

--
Andrew Gabriel

In article ,
antgel writes:
No, it is an electric hob.

OK, forget what I wrote before.

What's the power rating of:
The hob,
The oven,
The microwave?

Electric hobs can't normally run on a 15A circuit to start with.

--
Andrew Gabriel

In article ,
antgel writes:

Oven = 2.3
Hob = 6.3
Micro = 1.9 or 3 depending on whether I go for the one with the
conventional oven built-in.

This totals 10.5 or 11.6. Is 30A enough for this? I don't think so, if
your calculation before is anything to go by.

The hob will need wiring in to a dedicated 30A circuit.
The other two could go on a second 30A radial circuit.

--
Andrew Gabriel

Oven = 2.3
Hob = 6.3
Micro = 1.9 or 3 depending on whether I go for the one with the
conventional oven built-in.

This totals 10.5 or 11.6. Is 30A enough for this? I don't think so,
if
your calculation before is anything to go by.

Doesn't the '10A + 30% of remainder, plus 5A if outlet fitted with a
socket' diversity formula apply?

If so, it's about 19.2 amps for the hob/oven.

The microwave is either 8.2 or 13A, but would be permissible if plugged
into a socket on a cooker switch/socket unit.

Andrew Gabriel wrote:

The hob will need wiring in to a dedicated 30A circuit.
The other two could go on a second 30A radial circuit.

Is there a leagal/practical reason for this Andrew? As our electrician
ran 10mm sq feed for hob as a precaution which he has now had to take a
spur from the hob outlet to the oven as the oven is 3.5 KW so can't be
pluged into a 13 A socket.
He has also suggested we need to swap out the 30 Amp breaker for a 60
Amp naturally as the hob is 10 KW

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

In article ,
"Pet @ www.gymratz.co.uk" writes:
Andrew Gabriel wrote:

The hob will need wiring in to a dedicated 30A circuit.
The other two could go on a second 30A radial circuit.

Is there a leagal/practical reason for this Andrew? As our electrician

The hob needs 26A. The others to too high power to go on
same 30A circuit, and as they are designed for 13A outlets,
there's no easy way to put them on a circuit greater than
30A, so the hob would need to stay by itself on a 30A
circuit, and you need a separate circuit for the 13A plug
devices. They might be able to share a radial or ring with
other appliances, but they're already the best part of 30A
themselves.

ran 10mm sq feed for hob as a precaution which he has now had to take a
spur from the hob outlet to the oven as the oven is 3.5 KW so can't be
pluged into a 13 A socket.
He has also suggested we need to swap out the 30 Amp breaker for a 60
Amp naturally as the hob is 10 KW

That sounds OK providing you have a 60A cooker switch and
both appliances state they are OK with a 60A MCB. Not sure
what you mean by a 'spur' though -- an FCU can't supply any
more current than a socket.

--
Andrew Gabriel

Andrew Gabriel wrote:

That sounds OK providing you have a 60A cooker switch and
both appliances state they are OK with a 60A MCB. Not sure
what you mean by a 'spur' though -- an FCU can't supply any
more current than a socket.

Sorry, didn't mean a spur. it's configured with a length of wire from
the cooker outlet point (the wall thingy that the hob's leads connect
to) to a 2nd cooker socket behind the integraded oven from which it will
be wired. so still within max. current rating of coocker sockets.

It was originally wired with normal plug points for the oven & Microwave
as I was expecting it to be a plug-in appliance. Just goes to show how
inconvienient a few extra 100W can be.

Cheers
Pete
--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

On Mon, 27 Jun 2005 16:25:00 +0000, Pet @ www.gymratz.co.uk wrote:

Andrew Gabriel wrote:

That sounds OK providing you have a 60A cooker switch and
both appliances state they are OK with a 60A MCB. Not sure
what you mean by a 'spur' though -- an FCU can't supply any
more current than a socket.

Sorry, didn't mean a spur. it's configured with a length of wire from
the cooker outlet point (the wall thingy that the hob's leads connect
to) to a 2nd cooker socket behind the integraded oven from which it will
be wired. so still within max. current rating of coocker sockets.

It was originally wired with normal plug points for the oven & Microwave
as I was expecting it to be a plug-in appliance. Just goes to show how
inconvienient a few extra 100W can be.


In general I find built-in/under SINGLE ovens to be 13A or less whereas
double (or 1 & 1/2 ovens to be more accurate) usually need a 20A supply.

However there is no reason why such an oven (20A) and hob (26A) could not
share the same 32A dedicated radial circuit. Because the diversity
allowance for domestic cooking appliances is the 1st 10A at 100% and 30%
of the rest. This means that a 46A cooking appliance or set of appliances
only needs a supply of 10+ 36*0.3 = 20.8 A which is comfortably within 32A.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Ed Sirett wrote:

However there is no reason why such an oven (20A) and hob (26A) could not
share the same 32A dedicated radial circuit. Because the diversity
allowance for domestic cooking appliances is the 1st 10A at 100% and 30%
of the rest. This means that a 46A cooking appliance or set of appliances
only needs a supply of 10+ 36*0.3 = 20.8 A which is comfortably within 32A.

I think I follow your reasoning Ed.

I did actually say to our Electrician we could leave the 30A breaker in
until such time as it tripping becomes a pain as the likelyhood of
having 5 rings on flat out and 3.5 KW of oven flat out would be
remarkably un-likely, and that the oven (and rings)would only be on full
current during getting up to temp at the hottest setting after which it
would be considerably lower.

Thankyou for putting my ming at ease.

:¬)

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

Pet @ www.gymratz.co.uk wrote:

However there is no reason why such an oven (20A) and hob (26A) could not
share the same 32A dedicated radial circuit. Because the diversity
allowance for domestic cooking appliances is the 1st 10A at 100% and 30%
of the rest. This means that a 46A cooking appliance or set of
appliances
only needs a supply of 10+ 36*0.3 = 20.8 A which is comfortably within
32A.


I think I follow your reasoning Ed.

I did actually say to our Electrician we could leave the 30A breaker in
until such time as it tripping becomes a pain as the likelyhood of
having 5 rings on flat out and 3.5 KW of oven flat out would be
remarkably un-likely, and that the oven (and rings)would only be on full
current during getting up to temp at the hottest setting after which it
would be considerably lower.

In reality a type B 32A breaker will supply 46A almost indefinitely
without tripping... So if your total maxmimum load is 46A, it is highly
unlikely you would ever see a trip since the max load will only exist
for a shortish duration even if you do turn everything "full on" since
there will be thermostatic control being exercised that will lower the
average current demand.

Thankyou for putting my ming at ease.

I am glad to hear that your ming in now rested ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/