Electric Kiln

[OldJake]

My other half has just bought a small kiln for doing ceramics and the like. The kiln is specifically aimed at the hobby end of the market so it's single phase, 13a and 3kw with a standard 3 pin plug in terms of the spec.

We have an old (ish) house but have a new consumer unit and have had the garage (where the kiln will go) rewired about a year ago. The garage has a feed from a spur/junction box on the circuit for the back of the house which has its own breaker on the consumer unit. The garage also has a 13a fuse box on the electric supply.

If the kiln is drawing close to 13a all the time that it's on, how does this play with other things on the same circuit? I always thought the total for each circuit couldn't exceed 13a. So what if the kiln is running and there are other things on? Or is it a case that each outlet has a maximum rating of 13a? There must be a limit to the number of amps that each circuit will take. Just off the top of my head, that circuit has the washing machine, tumble dryer, a fridge, a freezer and a few other appliances. Plus the kiln. What if they're all on at the same time?

I just want to make sure that we're all safe before we fire this thing up!

 

[flameport]

? I always thought the total for each circuit couldn't exceed 13a

Assuming the circuit was designed and installed properly, the maximum load for the circuit is whatever the circuit breaker is rated for.

A 13A plug is not appropriate for a kiln, which by it's design will be on at full load for hours at a time. Neither is it appropriate to connect a 3kW kiln via a 13A fused spur, whether that is in the garage or elsewhere. The fuse will overheat and very likely cause damage.

 

[OldJake]

I'm not questioning your theory but this is the kiln:

https://www.cromartiehobbycraft.co....-13-Amp-KilnMaster-Controller-Furniture-KM714

They do 2 models of this particular kiln and this one is specifically aimed at being used with a 3 pin plug.

 

[SUNRAY]

A 13A plug is not appropriate for a kiln, which by it's design will be on at full load for hours at a time. Neither is it appropriate to connect a 3kW kiln via a 13A fused spur, whether that is in the garage or elsewhere. The fuse will overheat and very likely cause damage.

Are you seriously stating BS1363 is not fit for purpose?

 

[OldJake]

Are you seriously stating BS1363 is not fit for purpose?

So, do you think we're good to go?

 

[conny]

Yes. Perfectly safe otherwise a 13A plug would no be fitted.
If, in the unlikely event, you do have every appliance on the circuit running at maximum load you may find the mcb will trip. Simple solution is to turn off one, possibly two, high load appliances, (tumble dryer), until some of the others have finished.

 

[OldJake]

Yes. Perfectly safe otherwise a 13A plug would no be fitted.
If, in the unlikely event, you do have every appliance on the circuit running at maximum load you may find the mcb will trip. Simple solution is to turn off one, possibly two, high load appliances, (tumble dryer), until some of the others have finished.

Thank you. My biggest fear was that the wiring would heat up and possibly be damaged. I think the wiring from the garage to the spur will be fine as it's only a year old. It's the wiring from the spur to the consumer unit that I'm not so sure about. I have no reason to doubt it, it's just an unknown. But my realistic fear is pretty must as you've stated... that the breaker will trip and we just take a sensible approach.

There's a spare slot on the consumer unit. What I might do in time is get someone to run the garage to that so at least the garage will be on its own circuit.

 

[Harry Bloomfield]

Yes. Perfectly safe otherwise a 13A plug would no be fitted.
If, in the unlikely event, you do have every appliance on the circuit running at maximum load you may find the mcb will trip. Simple solution is to turn off one, possibly two, high load appliances, (tumble dryer), until some of the others have finished.

As it will regularly be expected to supply close to its current limit, I would make doubly sure the actual socket is a really good top quality one, with good tight terminals.

 

[bernardgreen]

Are you seriously stating BS1363 is not fit for purpose?

My experience is that some makes of 13 amp plugs and sockets do fail in a relatively short time ( a few months ) when running at 13 amps for several hours a day.

 

[winston1]

So you have a 13A fused spur feeding a 13A “fuse box”? in the garage feeding at least one 13A plug at full load.

Three 13A fuses in line is a crap design especially when at full load.

What is this 13A fuse box in the garage? Never heard of a 13A fuse box. You don’t need it anyway if you are running on the fused spur.

Also just make sure nothing else in the garage is switched when running the kiln, including all the lights.

 

[chivers67]

I'm looking at this and am thinking you're purchasing a piece of equipment that's worth nearly £1400 but you're not prepared to improve the power supply that feeds it? Do you know the actual Voltage of your supply in this instance? I know the Kiln doesn't look very big but it is is indeed running on near to maximum power for lengths of time I'm surprised it's fitted with just a plug.

Can you get a dedicated feed run into your garage for the Kiln ? Say 4mm ? or 6mm if you have other stuff in there?

 

[OldJake]

I'm looking at this and am thinking you're purchasing a piece of equipment that's worth nearly £1400 but you're not prepared to improve the power supply that feeds it? Do you know the actual Voltage of your supply in this instance? I know the Kiln doesn't look very big but it is is indeed running on near to maximum power for lengths of time I'm surprised it's fitted with just a plug.

Can you get a dedicated feed run into your garage for the Kiln ? Say 4mm ? or 6mm if you have other stuff in there?

I didn't say I'm not prepared to change the wiring. The wiring has been recently replaced. And it was bought on the basis that it was "plug and play" and should just plug into a standard outlet. Bearing in mind the company we bought it from are well respected, I was just taking them at their word. But I just wanted to sanity check what I was being told.

 

[bernardgreen]

I'm surprised it's fitted with just a plug.

"Just plug it in" or "just get an electrician to connect it "

Which of those is going to have the most sales,

Looking at the sales data this version has fewer operating modes than the version that has to be hard wired to a 16 amp supply.

But still the idea of 13 amps continuous draw from 13 amp plug is not good.

Also it is rated

Single Phase / Volts 230 / 13 amps / Watts 3000

and being resistive heating when the supply is 253 volts ( 230 +10% tolerance ) the current drawn is likely to be 14.3 amps.

 

[Tigercubrider]

My experience is with bigger (3phase) kilns but they don't run flat out all the time

Some (ours) runs via a programmer that heats for ten minute cycles and slowly brings the temperature up. You need to drive out any residual moisture and air. Once the pre cycle is over, it will slowly ramp up the temperature in stages to get to a maximum and then slowly climb down to allow cooling

It's not like whacking a massive oven or kettle on

 

[Tigercubrider]

Kilns are not ovens.
They cycle power to dry out moisture and drive out trapped air, slowly going to set temperatures in stages and turning off again. Over time they will build up to high temperatures but do this in stages and then slowly climb back down
The power is not on "heat" for most of the time. The lining retains heat and is boosted now and again to acquire the programmed stages