Hi

I am replacing a built-in oven. The existing oven connects via 6mm T&E
directly to the consumer unit (there is no junction box near the
oven).

Please can anyone point me to regulations for connecting a built-in
oven? Is a local junction box / fuse unit required?

Also, please can anyone point me to the current carrying capability
for 6mm T&E ?

Best regards

David

On Jun 11, 9:11*pm, DavidA wrote:
Hi

I am replacing a built-in oven. The existing oven connects via 6mm T&E
directly to the consumer unit (there is no junction box near the
oven).

Please can anyone point me to regulations for connecting a built-in
oven? Is a local junction box / fuse unit required?

Also, please can anyone point me to the current carrying capability
for 6mm T&E ?

Best regards

David

http://wiki.diyfaq.org.uk/index.php?...ing_capac ity


NT

Hi NT

Thanks for the link to the cable info.

Does anyone have any thoughts on my other question:

Please can anyone point me to regulations for connecting a built-in
oven? Is a local junction box / fuse unit required?

David

"DavidA" wrote in message
...
Hi NT

Thanks for the link to the cable info.

Does anyone have any thoughts on my other question:

Please can anyone point me to regulations for connecting a built-in
oven? Is a local junction box / fuse unit required?

David

What does the installation manual say regarding the fuseing?

Cheers

Adam

What does the installation manual say regarding the fuseing?


Good point. I will download it and have a look.

Thanks

David

What does the installation manual say regarding the fuseing?

Th Neff manual states:

"In the installation, there must be an all-pin isolating switch with
at least 3mm contact gaps, or the appliance must be connected using a
plug with an earthing contact. This must remain accessible after
installation."

I can't see that a plug is an option, because the oven is rated at
5.7kW. So does that mean I need some kind of oven isolating switch,
or will the MCB at the consumer unit be sufficient?

David

Sorry, I have just realised that there is an isolating switch for the
oven, but it is at least 3m from the oven. Am I right in thinking that
the Building Regs require the switch to be within 2m of the oven?

Would this not apply to me because it is an existing installation?

Best regards

David

On Jun 14, 8:12 pm, DavidA wrote:
What does the installation manual say regarding the fuseing?

Th Neff manual states:

"In the installation, there must be an all-pin isolating switch with
at least 3mm contact gaps, or the appliance must be connected using a
plug with an earthing contact. This must remain accessible after
installation."

I can't see that a plug is an option, because the oven is rated at
5.7kW. So does that mean I need some kind of oven isolating switch,
or will the MCB at the consumer unit be sufficient?

David

is it a double oven? have you added up both ovens ratings to get to
5.7kw?

if so google "diversity electrical"

Cheers
Jim K

On Mon, 14 Jun 2010 12:12:31 -0700, DavidA
wibbled:

What does the installation manual say regarding the fuseing?

Th Neff manual states:

"In the installation, there must be an all-pin isolating switch with at
least 3mm contact gaps, or the appliance must be connected using a plug
with an earthing contact. This must remain accessible after
installation."

Let's assume "all pin" means L+N which is almost certainly what they
really mean. You generally don't switch the earth out.

I can't see that a plug is an option, because the oven is rated at
5.7kW. So does that mean I need some kind of oven isolating switch, or
will the MCB at the consumer unit be sufficient?

David


Well, they do 32A "commando" plugs. Likely in a commercial kitchen but
you probably don't have room - they're fairly lumpy buggers - would take
a chunk out of one of your cupboards and you wouldn't be able to fit one
behind the cooker.

Standard 2 pole cooker isolator will be fine.

The MCB as an isolator will not be fine for two reasons: firstly, nearly
all[1] domestic MCBs/RCBOs are single pole (L only). Secondly it will be
far removed from the device. Local isolation is a good idea (can't
remember if it is positively required). If it is hideously difficult to
fit a local isolator, I or someone else here will no doubt be able to
look up the regs chapter and verse if you ask.

[1] I do have a couple of DP RCBOs - but they are far from normal.

Re fusing: 32A MCB at the CU will be the nearest rating. Your oven draws
more than 20A which would be (AFAIK) the next common rating down. It's
possible the oven manual might suggest a 20A MCB based on its load
characteristic[2] which is why the question was raised, but in the
absence of any other information other than 5.7kW, it would be a
reasonable assumption to go with the 32A MCB.

[2] eg it might pull 5.7kW for a short while from cold then the
thermostat will cycle it to a lower average power draw. Unlikely I would
have thought - it will probably take some time to reach operational
temperature. My combi can preheat to 250C in about 5-6 minutes, but it's
fairly little and fan assisted. Bigger ovens IME take rather longer.

6mm2 cable will be fine under these conditions unless it is run is a
cruelly non optimal way (eg bundled with a bunch of other cables, hot
water pipes and buried in insulation!)


--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

On Mon, 14 Jun 2010 13:30:51 -0700, DavidA
wibbled:

Sorry, I have just realised that there is an isolating switch for the
oven, but it is at least 3m from the oven. Am I right in thinking that
the Building Regs require the switch to be within 2m of the oven?

Would this not apply to me because it is an existing installation?

Best regards

David

The IEE OnSite Guide (17th) says 2m specifically, but does not cite a
specific regulation. Skimming through section 537 in the actual regs
which deals with isolation and switching, I don't see any reference to
cooker circuits or kitchen appliances (though I may have missed it - oh
for a searchable PDF!).

It is possible that this is drawn from some other non IEE regulation or
it's also possible that it is merely accepted good practice and you could
ignore it as long as you do have an isolator somewhere if meeting 2m is
impractical.

Any comments from our more informed members?



--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

On Mon, 14 Jun 2010 21:22:29 +0000 (UTC), Tim Watts
wrote:

On Mon, 14 Jun 2010 12:12:31 -0700, DavidA
wibbled:

What does the installation manual say regarding the fuseing?

Th Neff manual states:

"In the installation, there must be an all-pin isolating switch with at
least 3mm contact gaps, or the appliance must be connected using a plug
with an earthing contact. This must remain accessible after
installation."

Let's assume "all pin" means L+N which is almost certainly what they
really mean. You generally don't switch the earth out.

In fact it's _very_ bad practice to switch the earth, from a bonding
point of view.

The isolator for my Bosch double oven doubles up for the (also Bosch)
ceramic hob - both are (as the crow flies) within about a yard of the
isolator inside a cupboard almost below the hob.

(Within that self same cupboard is my stash of real tungsten lamps,
btw). And a few other things...

--
Frank Erskine

On Jun 15, 12:53 am, Frank Erskine
wrote:
On Mon, 14 Jun 2010 21:22:29 +0000 (UTC), Tim Watts
wrote:

On Mon, 14 Jun 2010 12:12:31 -0700, DavidA
wibbled:

What does the installation manual say regarding the fuseing?

Th Neff manual states:

"In the installation, there must be an all-pin isolating switch with at
least 3mm contact gaps, or the appliance must be connected using a plug
with an earthing contact. This must remain accessible after
installation."

Let's assume "all pin" means L+N which is almost certainly what they
really mean. You generally don't switch the earth out.

In fact it's _very_ bad practice to switch the earth, from a bonding
point of view.

The isolator for my Bosch double oven doubles up for the (also Bosch)
ceramic hob - both are (as the crow flies) within about a yard of the
isolator inside a cupboard almost below the hob.

(Within that self same cupboard is my stash of real tungsten lamps,
btw). And a few other things...

the mind bugles :)

Jim K