On 06/04/2020 12:26, George Miles wrote:
But when an electrician gives the circuit an insulation test they cannot isolate the USB socket so what do they do?

Or do they need an isolating switch?

Simpler and easier not to have any.


Interesting point.

However, after some worked (a new CU) our system was tested to comply
with Part P etc.

I don't recall the tester asking if we had any USB chargers plugged in.
He may have.


A similar test was done later, when we has the Main Fuse uprated. Agian,
I'm pretty sure I wasn't asked about USB chargers plugged in that time.

The plug in ones use the same/similar circuitry and are generally on
24/7, along with things like TVs on standby etc.