DP isolators fitted by DNO's.

[securespark]

I have seen plenty on TN-C-S supplies that are DP.

However, the regs say,

In TN-C systems, the PEN conductor shall not be isolated or switched.

Does that make the DP isolators on TN-C-S systems contrary to regs?

I have looked through ESQCR 2002 to no avail.

 

[RF Lighting]

Surely the isolator is installed after the combined neutral and earth have been split, and therefor it is only switching the neutral rather than a PEN.

At least all the ones I have seen are






(I still dislike additional 'pointless' isolators)

 

[securespark]

This is where I need my camera....

Take your point about splitting the PEN. However, why do some DNO's fit only SP isolators to TN-C-S systems?

 

[stevesey]

Because they think there is little point in isolating the neutral if they know it's the same as earth? (And an SP is cheaper).