Can electrical overheating smell like sawdust?

[BertieBotts]

Bit of a weird one. I had gone to bed last night with the baby, DH sitting up because he has a cold and couldn't sleep. At around 2:30am I woke briefly and was suddenly aware of a very strong smell of what I initially took to be burning. As I was half asleep and didn't realise the time I shouted DH's name as I thought he had only just left the room. He came in and said he could smell it too, so we turned the lights on - no obvious smoke etc. Checked his plug strip, which he'd commented earlier in the evening had stopped working, and mine, and then he sniffed the oil heater we have in the bedroom and said "It's that" and immediately unplugged it, even though it was already switched off.

When I smelled the heater more closely, I couldn't smell anything like the smell I originally noticed. The heater smelled like hot plastic/metal, but the smell I had noticed, I thought was burning wood/paper, but later managed to identify as the smell when you drill a hole in wood or use it with an electric sander and the wood particles heat up. I don't know if that makes sense? So a kind of hot sawdust smell, rather than an actual burning smell.

The smell did go away after a while of the heater being unplugged, so I think it probably was that, but I can't find anything online about a hot sawdust-y smell, only a fishy smell or a smell like a gas leak. I've never come across the fish smell, it was closer to a gas smell than a fish smell, I suppose, but I wouldn't describe it as either.

Am I just going nuts? DH could definitely smell something as soon as he entered the room, so I wasn't completely imagining things.

I don't think so. More likely the heat was against something made of wood or possibly paper.

Modern lightbulbs don't get very hot, old filament ones, especially halogens, do. You haven't got any downlighters, have you?

Oil-filled radiators usually get no hotter than a teapot, so unlikely to overheat except if the flex connection was poor in the plug or by the internal switch. Other electric heaters can overheat if papers or a curtain or garment falls on them.

you mention an adaptor no longer working. Check the fuse and see what was plugged into it in case it was overloaded. Some of them are quite poor quality.

A thing that was overheating will often feel hot to the hand, even without touching it, especially if the room is generally cold. Sometimes it is things like hair straighteners that have been left on. Cheap chargers from market stalls or chinese ebayers can be very poor, but original ones from the phone company are well made.

If a plug or socket has a poor connection and overheats, you will usually see brown scorch marks if you unplug it.

I suppose you'd better get a smoke detector for your room, and one on the top landing ceiling if you don't already have one.

It was definitely the heater. I went to inspect it a bit today and see if it did the same thing when turned on with somebody awake and watching it in the room and found that of the two switches (I and II) the second one is now completely loose, it doesn't click any more, just rocks loosely from on to off. So I unplugged it again and won't be using it because I assume that means it isn't safe. Did manage to have a bit of a peek inside the casing through the vents, couldn't see any scorch marks or anything.

I will contact the company to see if they will do anything as we've only had it for 2 years. I couldn't see anything that had fallen down inside it, and it was more than 30cm away from anything on all sides. It has always sparked (inside the casing) when the thermostat clicked on or off. Don't know whether that means the connection was loose to begin with. I pointed it out but was told I was being paranoid - perhaps I should have reached out to the company in the first place.

We do already have smoke alarms in all rooms except the kitchen and bathrooms, so no worries there. I don't think any smoke was caused because we were shining a little torch around just after so it would have shown up in the beam most likely.

Totally normal LED bulb in the light fitting and it turned out DH was saying something about his phone not charging, not the plug (I misunderstood). I will only allow genuine chargers in the house after I read a report about counterfeit ones causing house fires.

From what you describe, I think there was probably a poor connection on the switch, which over time overheated and became worse.

It's normal for a thermostat to make a momentary spark when it turns off under load.

It was clicking on/off fine yesterday. Oh well. Good to know that the spark I saw before was normal.

A momentary spark is OK, but a fizz, crackle or sparking that lasts more than 1/50th of a second is not. Switches have a spring to make them snap fully open, if this is faulty or (in some very old switches) not present, it's possible to hold the contacts in a "not quite" position, which will burn them.

I wouldn't be able to tell you how many fractions of a second, but it was always just momentary. I guess that the broken switch must have had a dodgy spring. It's not old, it had a manufacture date of June 2019.