First time I've seen a melt down

[RichardIStone]

Hello,
as a relatively newly qualified electrician (mature trainee who completed his NVQ in 2023) today was the first time I've seen a melted plug. It was at a rental property and the tennant had a fan heater hanging on to what was left of the plug. I'm guessing that the fan heater had been left on a high current setting for a long period of time, is there a recommended max time that an appliance should draw 8 amps or more from a standard (ie not EV) socket?
The landlord says the tennant has overloaded the socket, the tennant says the wiring is at fault. I know what I think but I'd appreciate the thoughts of thise more experienced than me!
I've got photos but cannot see how to post them on here?
Thanks in advance
Richard

 

[RichardIStone]

Ahh, looks like I can attach photos now that I'm signed in!

 

[James]

A good quality plug and socket should be able to carry 10A indefinitely

you will never find out the exact cause, looks like a poor connection between the plug pins and the socket.
a corroded plug or partially inserted one would cause that.
on the other hand a socket that has had something permanently plugged into it for a long time (months or years) can become weaker as the springs creep and the pressure on the pins become weaker .
if a previous tenant had plug in child safety socket covers that could make the socket fail when a high power device is later plugged in.

 

[westward10]

Almost certainly a problem with the plug. Many fan heaters have a cord rated to the kw of the appliance, for instance a 1.0 cord and the same applies to kettles. Couple this with poor quality plugs it is going to get warm have seen it many times.

 

[Julie.]

That's not an issue with the fixed wiring, the heat damage is not located near the fixed wiring connectors.

It could be an issue with the plug wiring, a bad connection in the plug could cause heat to travel down the plug connection into the socket itself. However, this would usually be confined to the one contact, it would be pretty odd that both connections have the same problem! But in effect, the bad connection heats up the plug contact, this causes surface tarnish increasing the contact resistance to the socket - and the cycle repeats until the results you see.

I would think however, that the issue is a poor quality plug (or socket outlet) - a lot of cheap plugs off "the bay", or "amazon" are knock-offs with incorrect size contacts meaning that the plug and socket don't contact with the correct tension, leading to localised heating, - exactly as is seen here.

Edit:

Or as @James has said, insering these dangerous "safety socket covers" damaging the socket outlet itself is a likely culprit

 

[James]

Almost certainly a problem with the plug. Many fan heaters have a cord rated to the kw of the appliance, for instance a 1.0 cord and the same applies to kettles. Couple this with poor quality plugs it is going to get warm have seen it many times.

Although I agree that a problem with the plug could cause that issue, I think it would be a stretch to blame the tenants for the damage, assuming that the heater was bought from a reputable source and was ce marked, it should be suitable to plug in and use.

 

[7029 dave]

When your plugging in this type of load its essential to use good quality sockets and plugs.

 

[littlespark]

It’s a Hager socket, so the quality is there.

Not a problem with the socket… even a loose connection there, the “hot spot” would be on the terminal.

Without seeing what’s left of the heater plug, it certainly looks like loose connection between plug pins and socket…. Caused by whatever

 

[grumpyjohn01]

Fan heaters..esp those £8 specials are an absolute blight...I've dealt with a couple of burn ups recently with no apparent fault, just low quality carp designed to just barely function within spec.

 

[pc1966]

Fan heaters..esp those £8 specials are an absolute blight...I've dealt with a couple of burn ups recently with no apparent fault, just low quality carp designed to just barely function within spec.

Sadly that is the most likely answer - a heater bought legitimately that was actually a bit crap.

Long-unused plugs and sockets are a common problem with tarnishing, but that is a new-ish Hager socket (has UKCA mark so post-Brexit date) so unless it was an ancient plug with tarnished pins, most likely a new but crap heater.

 

[James]

The landlord says the tennant has overloaded the socket, the tennant says the wiring is at fault. I know what I think but

At the end of the day, the Tennant has NOT overloaded the socket. (assuming it was just the heater plugged in and not a multi plug with other things as well)

I can see this becoming a blame thing for who is responsible.

the landlord, presumably has done all that is required and the property has a valid EICR.
this means that he/she has done all that is required to ensure electrical safety.

the tenant has plugged in a heater that (as far as we know meets uk safety standards)

therefore, in my opinion the failure is due to one of the following.

faulty socket
faulty plug
wear and tear of either or both of the above.

So where do we go from here?
If it was my property then i would pay the electricians bill myself be done with it.
i would not consider it to be unsafe use of the property or be blaming anyone.

sometimes things fail and the consequences are damaged equipment.
in this case the tenant needs to replace a heater and the landlord needs to replace a socket.

Don't go down the route of pointing fingers as it will not get you anywhere, it is impossible to prove whether the plug or socket were faulty, but it is definite that one or both were.

 

[pc1966]

Don't go down the route of pointing fingers as it will not get you anywhere, it is impossible to prove whether the plug or socket were faulty, but it is definite that one or both were.

100% agree here.

The likely explanations (poor hardware) is not the responsibility of either the landlord or tenant, as poor quality but legally sold equipment is not something that the vast majority of the public would spot.