Isolated Shower still showing voltage

[shbrooks]

I'm attempting to replace an electric shower which started literally smelling fishy. Having turned off the shower at the breaker, I've found that the shower is still giving off a reading of 4v when the cord is off and 20v when the cord is on. 

 

Can anyone help explain what's going on?

[ProDave]

Capacitive / inductive coupling, together with a digial meter with a very high input impedance.  Nothing to worry about.

 

However before you bin the shower, the fishy smell is far more likely to be the isolator switch has failed and is typical of the smell given off when plastics like those used in switches are overheating.  Check / replace the isolator first.

 

Unless you are SURE the fishy smell is actually coming from the shower.

[shbrooks]

Thanks for your quick reply. So I can still fit the shower despite there being a low voltage reading?

 

If it is the isolator cord, what caused this to fail?

[shbrooks]

...the old shower is pretty poor anyway. It was to be set on heating setting 10 to get an averagely warm shower.

[ProDave]

Usual cause of isolator failure is one of the terminals not done up tight enough and overheating.  If that has happened the wire will be burned and you will have to pray there is enough slack to pull some through, cut back the burned bit and re terminate.

[shbrooks]

Is there any way of determining where any electrical fault might like if the isolator cord is fine?

[ProDave]

1 hour ago, shbrooks said:

Is there any way of determining where any electrical fault might like if the isolator cord is fine?

Unscrew the switch from it's back box and have a look.