Dimplex Quantum storage heater 150 - keeps melting 20amp double pole switch

[showerproblems]

Had a quantum (qm150) installed for 8 years - no problem.
Couple of weeks ago the switch (usually always on except when on holiday) stuck and no power to heater.
Had a look at switch and saw it was melted where the N wire goes in.
Bought an exact replacement (B+Q) and replaced myself with the same wires (one from E7 and one set from normal switches in house)- worked fine for about 10 days and then suddenly has stuck again with same N wire melted.

When researching on here for the problem, it was suggested that the switch may be at fault and to replace, which I did.

My question is now- should I replace with another 20amp double pole switch (maybe a better brand?) or should I use something else (Im not skilled at electrics beyond wiring plugs/replacing sockets etc) instead ?
Or is it a bigger job that need an a qualified electrician to look at ?
Like I said, it has been fine with no problems for 8 years, till now.

 

[littlespark]

For the size of heater, any 20A double pole switch should be ok.

Heating up at the terminal usually points to a loose connection.

If the cable has burned before… it’s better to cut off the burned end off and restrip the end to clean copper.

 

[showerproblems]

For the size of heater, any 20A double pole switch should be ok.

Heating up at the terminal usually points to a loose connection.

If the cable has burned before… it’s better to cut off the burned end off and restrip the end to clean copper.

Cheers.
It was exact same one I replaced- will try stripping the end like you suggest and putting in a new one and get back.

 

[littlespark]

Just another note.

If it’s a single core of cable, strip about an inch off, and fold it over. Fills the terminal hole better, and gives the screw two surfaces to hold onto.

Too much stripped off, or not inserted fully will show bare copper, which we try to avoid.

Heating up can also occur where a live terminal is too close to an earthed metal back box.
Take care if the box has unused screw lugs top and bottom as well as on the sides. They can end up really close when the switch is screwed back, and are best bent flat.

 

[showerproblems]

Just another note.

If it’s a single core of cable, strip about an inch off, and fold it over. Fills the terminal hole better, and gives the screw two surfaces to hold onto.

Too much stripped off, or not inserted fully will show bare copper, which we try to avoid.

Heating up can also occur where a live terminal is too close to an earthed metal back box.
Take care if the box has unused screw lugs top and bottom as well as on the sides. They can end up really close when the switch is screwed back, and are best bent flat.

Good tip- bought some wire strippers for this purpose.
Cheers

 

[showerproblems]

Follow up- Replaced the melted switch and so far so good.
I only have the storage heater and the hot water tank on E7,
looks like it goes from the water tank to switch and then on to heater.
The hot water switch gets hot (but doesnt melt) and I have tightened up connections there also,
but still gets warm.
Could this be a problem?