Kiln cable size

[geraldthehamster]

Hello, hope someone can help. I have acquired an electric pottery kiln, single phase, output 10.5 kW, rated at 47.7A. Is the existing 25m of 10mm cable from the house consumer unit to the garage likely to be of adequate size?

Many thanks

Richard

 

[PrenticeBoyofDerry]

It would depend on how the cable was routed to the garage and whether any derating factors need applying.
10mm cable can handle up to 63A but that would be in ideal conditions.

 

[flameport]

output 10.5 kW, rated at 47.7A.

So 10.5kW at 220V. Connecting that to a 230V or 240V supply will mean the current is more than 47.7A.

Is the existing 25m of 10mm cable from the house consumer unit to the garage likely to be of adequate size

Possibly, although likely to be marginal due to ambient temperature, and the installation method will be significant as well.

Installing such a device also requires approval from the DNO, details here: http://www.energynetworks.org/info/faqs/electricity-distribution-map.html

 

[geraldthehamster]

It would depend on how the cable was routed to the garage and whether any derating factors need applying.
10mm cable can handle up to 63A but that would be in ideal conditions.

Thanks. If this provides any more useful information, it runs from a consumer unit in the kitchen, along the eaves the length of a dormer bungalow (I believe not embedded in any insulation but will check), down the outside wall, then appears to go underground to emerge 5 metres further along at the consumer unit in the garage.

How would one calculate any derating, to judge whether the cable is OK?

Cheers
Richard

 

[JohnW2]

... it runs from a consumer unit in the kitchen, along the eaves the length of a dormer bungalow (I believe not embedded in any insulation but will check), down the outside wall, then appears to go underground to emerge 5 metres further along at the consumer unit in the garage.

What sort of cable is it - just ordinary 'house wiring ' ('flat twin and earth', with a grey or white outer sheath) cable or some sort of armoured (usually black and round) cable? Is it all one continuous length of cable, or does it change anywhere (perhaps where it goes underground)?

Kind Regards, John

 

[ban-all-sheds]

the existing 25m of 10mm cable

Why do you say that it's 10mm?

How would one calculate any derating, to judge whether the cable is OK?

These explain the general principles:

https://www.tlc-direct.co.uk/Book/4.3.9.htm

http://www.napitonline.com/downloads/CP 2 07 P 10-11 16th Cable Sizing 1 of 2.pdf

But please note that they are out of date - there are more and different factors to consider now. The IET Wiring Regulations, BS 7671 has all the current info.

 

[geraldthehamster]

What sort of cable is it - just ordinary 'house wiring ' ('flat twin and earth', with a grey or white outer sheath) cable or some sort of armoured (usually black and round) cable? Is it all one continuous length of cable, or does it change anywhere (perhaps where it goes underground)?

Kind Regards, John

It's grey sheathed flat twin and earth.

Cheers
Richard

 

[geraldthehamster]

Why do you say that it's 10mm?

Um, because I know what 10mm cable looks like?

Thanks for the links.

Cheers
Richard

 

[JohnW2]

It's grey sheathed flat twin and earth.

Thanks. How does it go underground - in some sort of conduit or ducting?

Kind Regards, John

 

[flameport]

Um, because I know what 10mm cable looks like? d

The reason for the question about size was that many people on this forum and elsewhere have incorrectly assumed that T&E cables are sized by the dimensions of the outer covering, with the result that what they thought was a '10mm' cable was in fact substantially smaller.

 

[geraldthehamster]

How does it go underground - in some sort of conduit or ducting?

Kind Regards, John

As far as I can determine from its emergence in the garage, in a plastic duct. Possibly a 32mm waste pipe

Cheers
Richard

 

[ban-all-sheds]

It's grey sheathed flat twin and earth.

Not suitable for use in a plastic duct underground.

 

[Taylortwocities]

Need answer to this question first

the existing 25m of 10mm cable

Why do you say that it's 10mm?
.

The size of a cable (e.g. 10mm² ) relates to the cross sectional area of the copper conductor. That is why cable sizes are quoted in mm² and not mm!!

A ROUGH guide to cable sizes can be determined by measuring the outside sheath of twin and earth cables. A table, and other information, can be found in the wonderful WIKI at //www.diynot.com/wiki/Electrics:flatpvccables

Supplementary question: what size fuse/MCB is in the consumer unit protecting this cable?

 

[bernardgreen]

Before spending money on the electrical supply check that the garage is a safe place to operate a kiln of that size.

There are safety aspects about operating a kiln that require minimum clearances around and above the kiln.

 

[geraldthehamster]

Before spending money on the electrical supply check that the garage is a safe place to operate a kiln of that size.

There are safety aspects about operating a kiln that require minimum clearances around and above the kiln.

Yes, thanks. I know this already but it never hurts to point it out.

Cheers
Richatd