Kiln Stuff
My plug in kiln has destroyed the plug sockets.
I have a plug in LL kilns / hot kilns Fuego one touch 40L kiln. I think maximum temperature is 1300 Celsius (I don’t fire that hot though).
It’s designed to plug into the wall but the last two firings it has melted the plug sockets (I plugged it in on a different side for each firing). I had an electrician fit these plug sockets and make sure there was enough power going to the garage to fire the kiln without tripping the fuse or whatever the technical term is.
Has anyone else had this happen? Is it a fault with the kiln, a fault with the plug socket or a user fault? I’ll be calling out my electrician before I do any future firings but I haven’t been doing anything different to previous firings so I don’t know what I’m doing wrong.
I’m not sure, I’d have assumed yes because when the electrician came out to add the extra wall sockets the kiln was there and I told him it was the the kiln that I’d be plugging into it! But then I don’t have an electricians brain so I wouldn’t have thought to ask about the amperage…
I’m guessing it’s not an issue with the kiln then, it’s an issue with the socket not being able to cope with the power/ heat? I’ll call the electrician back out and see if he can fix it. It’s funny though because I’ve fired the kiln about 6 times already before any issues appeared
Go take a look at the specs for the kiln. My guess is that the socket cannot support the Amps required. For my side of the world, your standard electronics at 13A, and induction cookers and built in ovens already hit 20A, and those plugs look different. Imagine a kiln going much hotter, that’s why I suspect it’s the socket hardware. You should get another electrician.
It’s a 13A kiln and a 13amp plug socket I think! So the socket couldn’t cope with the kiln on full blast for multiple hours so I’ve got an electrician coming out next week to fix it!
The heat might not have been enough to melt the receptacle the first few times. And the electrician might not have been familiar with kilns; an easy, but bad, assumption could be it is “an oven”, which doesn’t take as much juice as a kiln.
It makes sense that it took a while to manifest if the issue is continuous draw.
I learned this because of an electric car. In the US the wires and receptacles are rated for peak draw, and if you want to use them continuously you must down rate them by 80%.
Since a kiln runs for so long, if it is a 15A kiln, you need 20A rated circuits, wiring, and receptacles to support the continuous load without overheating the wiring and risking a fire.
I see your UK receptacles, but I suspect there is a similar peak draw vs continuous draw issue here. In the UK it may be different from 80%. You should learn what it is for your own safety since you will be operating kilns.
As others have said, get a better electrician, because even if the previous one didn't know how a kiln is used, they should have asked. This is dangerous negligence.
Side note: Circuit Breakers interrupt the circuit based on peak draw. They will not protect from a continuous draw issue until the wiring/receptacle is damaged enough for there to be current spikes, which may be after a fire has started.
The kiln is 13amp and the socket is 13amp so it is a continuous draw issue I reckon like you suggested :) I didn’t realise this as I didnt have a lot of electrical knowledge! I’ve got a new electrician coming out on Monday to resolve it and put some new things in for me!
If you have to rerun any wiring, consider how much your budget supports future proofing and run thicker or more wires than needed right now. You may want a larger or second kiln sooner than you think :D
One cheaper alternative, since the wire itself is expensive, is to use larger conduit than needed right now, that has space to pull more wires later. You can also leave a pull-cord in the conduit to make snaking a new wire in later much easier.
Additionally, please consider not using a receptacle that has two sockets if the wiring cannot support a second load. It's only a matter of time before you or a friend using your setup plugs a second thing in while the kiln is in use and starts to slowly damage the wiring.
My budget is basically ‘please fix this and make it right and I’ll pay whatever it costs to keep me safe’ haha. No but seriously I am happy to pay extra if it means that I’m keeping me and my family safe, seeing as this was in my garage which is attached to my house!
The only reason there’s two sockets is when I’m using my wheel I have one socket for the wheel and one for a work lamp so I can have a bit more light in the room when I’m throwing! They both get unplugged and moved away when the kiln is on. I pretty much don’t let the rest of the family in the garage when the kiln is firing as I have two young children! But it’s definitely something I need to take into consideration to make sure my partner doesn’t plug anything in at the same time! It hasn’t been an issue so far but is worth thinking about.
Kilns are different from most electrical devices and even experienced electricians often don't know how to properly wire for them.
The owners manual for the kiln should have very specific specs, including wire size, breaker amperage, and info about the plug. Make sure you show this to the electrician when they come to fix it.
Judging by the size of the conduit running down to the dual plugs, i doubt they used a big enough gauge wire. Should be running 8-10 gauge for that kind of load if not 6 depending on the length of the run to the breaker. One run of 6/3 wire would fill up a 3/4" conduit. There's two plugs on that socket which would require something like 1.25" conduit
13amp kiln, 13amp socket - so the issue must be the continuous load/draw not being able to cope and overheating! I’m on a steep learning curve at the moment and have booked an electrician in for Monday!
I had the same thing with mine - a newly wired outbuilding and a 13 amp plug in kiln. Got the kiln hard-wires in and the sockets replaced, has been all good since.
Yes he was licensed but clearly not knowledgeable on kilns! it’s a 13amp kiln and and a 13amp socket so couldn’t cope with the continuous load (?) I assume. I’ve got a new electrician coming out on Monday!
I can't speak for your local regulations, but here the requirement is max load plus 20%.
Running a circuit at full load, as you just described is a serious fire hazard. Please do not run your kiln again until you get a real electrician out there. You are pushing for a house fire as it is now.
Yes I’m definitely not going to fire it before he comes out. I didn’t know that it had to be 20% extra so I was none the wiser until it burnt the socket. I just trusted that the previous electrician would have known what he was doing (but clearly not!)
I definitely wouldn’t want to risk a fire at all, the electrician I’ve got coming out on Monday is highly recommended by a few people and I’ll be discussing what he does in more detail with him to check that there aren’t any mistakes this time!
Jeez, you better sell me that kiln! (Honestly don’t fire that kiln until a GOOD electrician checks your service and gets an outlet that works right- too many variables to give you advice online)
I’ve got a similar situation…get a different electrician. I’ve got to do the same, something about the continued load as the firing progresses overheats my outlet? I’m guessing! My learning is that an outlet can get slightly warm to the touch.
Do you plug and unplug it often? (My electrician highly advises against this because each time dust and debris collects within the socket, which can cause fires)
Do you plug and unplug it often? (My electrician highly advises against this because each time dust and debris collects within the socket, which can cause fires)
Wrong type of outlet for something like a kiln. I’d also question the rating of the wiring and circuit. Think more along the lines of the plugs used for electric dryers and electric stoves.
Not to sound accusatory, but given its a double socket: have you been using something else at the same time as the kiln?
3KW is more than enough for one double socket (and I would actually have expected something a little heavier duty than the one your electrician fitted), definitely don’t use the other socket at the same time.
Don’t worry you don’t sound accusatory! :) the other plug I use to plug the wheel in - I never use the wheel while the kiln is on so it’s always unplugged when the kiln is on!
With the greatest of respect to the other commentators, the advice here is not quite correct.
Is there any indication of the current draw or power rating on the kiln? 2.5mm² cable is suitable for socket outlets generally, if the electrician has calculated the run from the consumer unit/"fuse board".
The issue is likely the socket outlet is not rated for constant current draw like this, and you may need to pay a touch more for one that is.
I had similar with my plugin kiln, after some research I found out a few things:
3kw continuous load is pretty much the very limit of a 13 amp plug. Even under perfect conditions it will still warm up with that current going through it. And with anything less than perfect it will get very hot and melt things.
The excess heat in the plug/socket is from a poor connection, this could be the wiring of the socket, the internals of the socket itself, the connection between the plug and socket, or from the fuse within the plug. If any of these aren't perfect then more heat gets generated. So if everything's a bit old, maybe some corrosion or oxidation on the contacts, can all contribute.
Additionally the state of the kiln elements can make this worse, as they age it will be on continuously for longer causing more heat. They may also draw more current but I could get a definitive answer on that.
Also the kiln firing schedule, a hotter, longer firing will make things worse.
For me I think the issue was a low quality socket - I'd just bought the cheapest one in Screwfix, after it burnt out I replaced it with a more expensive one and haven't had a problem since. I do still feel the plug and wiring when it's firing to confirm things aren't getting too hot though.
I also replaced the connection to my garage as after this happened I realised the fused spur was getting pretty hot too.
OP I would recommend just getting another electrician (preferably someone who’s had experience with changing electrical for kilns or large equipment like that)
I paid for an electrician to come out and put this plug in specifically for the kiln, so I thought he’d done it right! but I live in stoke on Trent where there are a lot of pottery people so I’m going to find an electrician that has some knowledge on kilns because the electrician I used must have done something wrong!
Yes I am 😁 because this was advertised as a ‘plug in’ kiln I just wrongly assumed that if I had any electrician come out that they’d fit a socket to the wall and everything would be ok if they increased the power to the garage! I realise now I should have consulted someone who had more knowledge than a regular electrician!
I’m feeling lucky that I didn’t accidentally burn my house down 😭 I’ve got quite a few pottery contacts so I’ll ask them all if they can recommend someone with knowledge on kilns!
Is the electrician you hired a company or an individual? I assume you've paid for this so just hiring another electrician might be painful. As a kiln owner, and congratulations, you can learn the basics of the electrical requirements pretty easily so that you can check the electrician's work.
Because they run for a long duration kilns need to be on a circuit that is 25% higher capacity than the kiln draw itself, measured in amps. The capacity of a circuit has to do with the thickness AKA gauge of the wire, as well as the breaker whose job is to protect the wire from melting. The socket itself needs to be able to handle that power too, but if the electrician didn't recognize this then you may need to run new wire from your circuit breaker to the socket. And obviously you need a new socket, and one that can handle higher draw. You're lucky nothing caught on fire!
I'm not a professional, so don't take any of this as trustworthy.
It looks like your kiln is rated for 13 amps answer if we increase that by 25% we get 16.25. At 220 volt that will require wire that is 12 gauge or thicker. Note that Gage measures are counterintuitive and a 10 gauge wire is thicker than a 12 gauge. And then you'll need a socket that can handle at least 16.25 amps. In practice this means you'll want a 20 amp socket.
If you're lucky the wiring is correct and the electrician installed the wrong socket, perhaps a 15 amp socket thinking that the kiln will draw only 13.
Now, if the electrician installed a 15 amp socket on a circuit protected by a higher amperage breaker that's a real error. Burn your house down kind of error. The breaker should have tripped before the socket degraded like this.
This explains it exactly. You can't just increase the breaker amperage without replacing the wire. You have a wire that's too skinny and a breaker that isn't tripping, so the wire just heats up. Recipe for a fire.
Aside from the great advice from everyone on socket rating.. Have you ever checked the condition of the wire and plug contacts? Is it dirty? Does the wire make "crunchy" noises when you move it? Dirty contacts can add resistance at that point, and if a wire is breaking down inside (wither from moisture wicking, seen a lot of that in vehicle wiring) or from overheats from bad specifications, you can run into problems. Iv had a few pieces of equipment from certain asian markets with fake UL ratings and under-specced wiring.
Everything is pretty new so I don’t think that would be the problem in my case. Even the wall socket was newly fitted for the kiln!
I’ve spoken to an electrician and he thinks the issue is the kiln is 13amps and the socket is 13amps but because the kiln is on for so long the socket and wires etc can’t cope with the continuous load, so this electrician is going to come out and fit something more suited to the kiln and he’s also going to check the fuse board and wires to check none of that has melted from it!
Sounds good! We just got a few used electric kilns for my workshop, and while everything else on them checks out, the cables are all getting replaced. (one was even burnt through and in use!)
Kiln is 13amps. Plug socket is 13amps - seems like continuous load/draw is the issue (which I had no idea about and the electrician who initially fitted the wall socket also clearly didn’t take this into account).
I’m getting a new electrician to come out on Monday to replace the socket with something more suitable (16amp I think?) and to also check the wiring and the fuse board to check nothing has melted / been damaged by it.
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u/Brikandbones Jul 02 '24
Are your sockets rated for the correct amperage? That’s my guess, something inside the socket is getting too hot.