Could this fuse be blown?

jsmoke

jsmoke

jsmoke

Soldato
Joined
17 Jun 2012
Posts
11,259
Think it's called a thermal fuse(but aren't all fuses thermal fuses?). Looks ok from the outside but could it be blown in the inside?

30ianhy.jpg
 
Obviously not recommended as a permanent solution but you could also test if the fuse is bad by joining the two blue wires together to bypass the fuse.

If you have a multimeter you could just stick a probe on either side in continuity mode and see if it reads 0 (good). If you don't have a multimeter go buy a cheap one for ~£10 because they're incredibly useful for testing batteries, wires etc!
 
jsmoke said:
Think it's called a thermal fuse(but aren't all fuses thermal fuses?). Looks ok from the outside but could it be blown in the inside?
Click to expand...

It could be blown, you need to do a continuity test.

As to the first part of the question, I think there is a little confusion here, at their basic level all fuses work on a thermal level, an overcurrent causes increased power disapation in the fuse element which causes it to melt an interupt the circuit. However what you have here is not an overcurrent protective device, its a thermal protetive device, it goes open circuit on a set termperature (printed on the side) being exceed and is non resetable. They are used in heating appliances to protect against failure modes such as thermostat welding shut or airflow path being blocked to prevent fire from the appliance getting hotter and hotter from the failure. YOU MUST NOT BYPASS THIS (other than as a poster above says, a very quick bench test)
 
Thanks. I'll bench test then for a min. Yes it's from a heater. Hope the bench test doesn't fry or blow anything up.

I've read that I can't just solder a new fuse and wire on that you need to crimp, I assume the heat would melt the solder?
 
That's 110C thermal fuse.
They're used as safety measure to make sure devices don't overheat and potentially cause fire.
So for monitored short term testing bypassing it is OK.
If there's short circuit thermal fuses aren't anyway meant to protect from those.

And because they're always in series with load hey don't have to be removed from circuit for testing.
Resistance should be pretty much zero if its functional or out of range if "broken".


Pho said:
If you don't have a multimeter go buy a cheap one for ~£10 because they're incredibly useful for testing batteries, wires etc!
Click to expand...
While usually not having real capability for required user protection in advertised class those cheap meters work when staying away from higher current mains voltage sources.
https://en.wikipedia.org/wiki/Measurement_category
http://testmeterpro.com/multimeter-safety-and-input-protection/
Yep, meter used in checking 230/240V where it comes to main fuse box of house has to protect user from certain length 12kV peak/surge...
 
EsaT said:
While usually not having real capability for required user protection in advertised class those cheap meters work when staying away from higher current mains voltage sources.
https://en.wikipedia.org/wiki/Measurement_category
http://testmeterpro.com/multimeter-safety-and-input-protection/
Yep, meter used in checking 230/240V where it comes to main fuse box of house has to protect user from certain length 12kV peak/surge...
Click to expand...

Yeah I wouldn't recommend the OP go poking around the mains with the cheapest meter you can possible find but for quick continuity / battery checks they're going to be fine.

Mind you I've checked for mains plenty of times with cheap / mid-range meters but I do try and do so safely. Then again, I'm also the person who once grabbed a PC kettle lead wondering why it wasn't working only to find a mouse had chewed through it leaving bare wire which I grabbed on to giving me a quick shock of electric :o.
 
Yes and no. It is if you have the correct equipment, but if you don't its likely to end up a bad joint, those crimps in the picture are machine applied, depending on the size of the wire leads you might get away with through crimps for 1 / 1.5mm². But then you'd need the correct rachet crimper and then have the issue that the crimps would likely to be-insulated with plastic which might or might not be able to handle the temperatures... that looks like silcon rubber insulation on the conductors which is good to about 180C I think.

It might be easier to get a couple of pocelain conenctor blocks ( https://www.google.co.uk/search?cli...ocjXAhXKVRoKHUs3ChkQvwUIIygA&biw=1266&bih=882 ) and use a screwed joint. Being porcelain they will be alright at temperatures at which the tough nylon or soft thermoplastic types would be damaged
 
Looks a good idea but I'm still going to have to wrap the fuse in two layers of rubber and then put a heat shrink layer over that(took them off for pic). What kind of place would do such a small job, Maplins?
 
You must log in or register to reply here.
Back
Top Bottom