This shower switch gave a spark and popping sound

[Jupiter01]

upon closer inspection, I can see that a large amount of the live cable is unsleeved but some of it is firmly in the terminal. I can also see that the earth cable is unsleeved. It’s very possible that these two came into contact.

Would this cause the pop and spark? How do I resolve this please?

 

[ericmark]

Loose terminals is likely cause, cable now damaged so isolater needs renewing and cable and cable cutting back if there is enough spare.

 

[terryplumb]

Yes its possible. The insulation doesn't look too good ,or maybe just a bad picture. Fit a new switch ,re make the connections and sleeve the earth conductors.

 

[bernardgreen]

Would this cause the pop and spark?

looks like the Live terminal was loose and this became hot enough to melt the insulation. This by itself would not trip any fuses.

The pop and spark would as you said have been when the insulation become soft enough for the un-sleeved Earth conductor to make contact with the Live conductor

 

[Jupiter01]

I don’t have much by way of spare cable. Am I okay to cut back to where it is unsleeved and pop it back in terminal of a new switch?

 

[terryplumb]

You need to cut back to good insulation ,and clean copper. Hopefully the cable will reach to the new switch. Can you not ease the cable further into the back box ?

 

[Jupiter01]

I will have a further look tomorrow and report back. Thanks guys

 

[Taylortwocities]

Replace the switch too, the terminal surfaces will now be carbonised.

 

[winston1]

Don’t operate it when the shower is running. Better still leave it permanently on except for when you want to do maintenance on the shower.

 

[333rocky333]

The back box looks broken as well

 

[Jupiter01]

The switch is on next day order.
Can I use a 30amp junction box to make this safe? I was unsure on the rating

 

[Taylortwocities]

What size cable is that, 6mm² ?
What size is the MCB for the circuit?

A 30A box may not be big enough.

 

[Jupiter01]

MCB is b40 and cable size is 18mm when measure from outside

 

[Taylortwocities]

You should know, by now, that cable size is by the cross sectional area of the copper conductors.
This table shows approximate sizes.
given the outside dimension of 18mm it would seem that you have 10mm² cable.

In answer to your question

Can I use a 30amp junction box to make this safe? I was unsure on the rating

The answer is NO.
the cable size is too big and the CPD size of 40A is too high for a 30A junction box.
You'll have to be smelly until the replacement switch arrives, or put the tin bath in front of the fire. Get your significant other to scrub your back!

 

[terryplumb]

Every 10 mm2 t/e cable That I have seen has a stranded CPC ,not solid as in the pic. Did they ever use solid ?