Suitability of domestic supply to power 14kW kiln?

[NozSpark]

Guys,

I've been asked to look at supplying power to a shed to power an electric kiln, it's 14kW and he also wants a couple of sockets and a light.. I recon a 70A sub main will do.

Now obviously this is connected to a house which will have a maximum of a 100A suppliers fuse (TNC-S) - I've told the guy to get his supplier to get an isolator fitted and while they're at it to assess his supply.

The demand of the house isn't much - gas cooker and central heating; and the guy lives by himself. He's also said that he'll only use the kiln at night.

What do you guys think about connecting this monster to his existing supply (assuming that he's got a 100A main fuse)??

BTW I don't need any help in the design of the submain or final circuits

 

[Evans Electric]

Put a 60A supply in and instruct him accoringly on not showering and cooking at the same time .

I've done a couple of kilns but not that big TBH , think they were 10KW .

 

[NozSpark]

Put a 60A supply in and instruct him accoringly on not showering and cooking at the same time . I've done a couple of kilns but not that big TBH , think they were 10KW .

Gas oven and shower off the combi...

But he needs more than 60A, he also wants to run some fish **** grow beds (in an adjacent poly tunnel) so there's a pump and possibly a heater in there:O

From what I gather he's only going to be using it to to slump glass bottles

 

[steptoe]

he also wants to run some fish **** grow beds

:slap

WTF is that?

made me laugh anyway.

 

[Steve3948]

Providing you can fuse it in such a way that your installation goes before the cut-out, then it should be fine, providing he sticks to the plan of using it at night.

I did one for a potter who wanted it on E7 for cost reasons, I've never been back so all must be ok.

"You sure he's not growing green plants on a large scale" haha

 

[PC Electrics]

Can you apply any diversity? Presumably, like an ordinary oven, this thing runs at full chat from cold untill it's up to temperature and then cuts in and out to maintain the set temp? How long does it take to get up to temp from cold?

TBH, I don't see it being too big an issue provided he's got at least an 80A main fuse. There's plenty of all electric houses pulling this much for 7hrs every night into a bank of storage heaters. And there's defo no diversity with storage heaters.

Presumably he's gonna get E7 to keep the running costs to sensible proportions? Hence the running at night bit?

 

[Steve3948]

Erm storage heaters start to cycle after about 20 minutes on the input stat.

 

[kerching]

On a slight aside...if it was me doing it I would fit a couple of NM/M3 bulkheads in as well.

Reasoning.....he works in there at night, it is dark, main breaker/fuse in house lifts, darkness ensues and Mr Sod and all his little in-laws come out to play. Darkness, trip hazards, on his own, hot kiln...no-brainer in my mind. There again, bloke on his own, in the dark, fiddling with ceramics, growing fish ****...not that I am drawing any conclusions..... :coat

 

[ProDave]

Up here (I don't know if it's the same elsewhere) a "normal" domestic supply is rated at 16KVA. If you want higher, you pay more and get a thicker cable.

But my own "16KVA" supply has a 100A fuse in the head, (I've been told by a meter monkey up here that's all they fit.) and has no problem running two 9KW showers at the same time.

So I can't see a problem with the kiln as long as you advise him not to use an electric shower at the same time the kiln is on.

If he's using it mostly at night, I would strongly suggest converting the supply to Economy 7 or better still Economy 10 so most of the kiln's usage will be at the cheap rate.

Thinking about that last statement, if he already has electric storage heating, then using the kiln at night when the storage heaters are charging up might not be the best plan.

 

[Steve3948]

Dave, Noz did not say he had Storage Heaters, PC said people have Storage Heaters giving the same type of load.

 

[NozSpark]

Thanks for the input guys,,, keep it coming

The fish grow beds have a 1000 litre tank for the fish which over flows into a filtration/growing bed which overflows into another filtration/growing bed and this then overflows into a sump which is then pumped back into the fish holding tank.... So it only really has a pump, but I recon that he might also have a heater in there in the Winter....HTH

As for the kiln, IIRC he did say that it had a controller (didn't see that and I had forgotten about it) with which he could adjust the rate of rise of temperature of the kiln, however it will always be on full chat while it is heating,,,,, I guess if he had it set to say 100deg/hr that it wouldn't be on for long before it got into a cycling mode,,,,, I don't know how "intelligent" the controller is

But like I have said,,

Gas central heating

Gas oven

Shower off central heating

Oh,,, and not on E7 or E10,, but it might be worth while for him to consider this, hadn't thought of that either:shakehead

 

[Evans Electric]

What do you reckon then Noz, allow for an 80A supply ........25 sq,mm X 2 core ? :C

 

[NozSpark]

What do you reckon then Noz, allow for an 80A supply ........25 sq,mm X 2 core ? :C

Might have to Deke:C

I was thinking that 16kW would be enough, so yes 25mm 2 core SWA with a 80A BS88

Still to do the calcs though

 

[Steve3948]

A lot of merchants will sell 3 Core cheaper than 2 Core, due to demand apparently, although I have never 100% believed them, as they all talk b******t most of the time.