Dual Tariff Supply where do you take the Ze

Michael J · Apr 30, 2019

Where do take the Ze on a dual tariff supply? At the 4 pole isolator (or do you change it to a circuit breaker)at the service head or in the consumer unit?If at the consumer unit which supply, the supply from isolator to consumer unit is a 16mm t&e. Your help will be greatly appreciated.

Deleted member 26818 · Apr 30, 2019

Technically, you have two installations.
So you can either measure Ze at each board, or if there is a single 4 pole isolator for both boards, you can measure there.

Michael J · Apr 30, 2019

spinlondon said:
Technically, you have two installations.
So you can either measure Ze at each board, or if there is a single 4 pole isolator for both boards, you can measure there.

The supplies are in one board and they are fed from the 4 pole isolator. Why I am asking for advice is the 16mm T&E has a 6mm cpc which is obviously not 16mm.

Deleted member 26818 · Apr 30, 2019

Is the 4 pole isolator sealed?

Michael J · Apr 30, 2019

[ElectriciansForums.net] Dual Tariff Supply where do you take the Ze

spinlondon said:
Is the 4 pole isolator sealed?

Deleted member 26818 · Apr 30, 2019

So the isolators aren’t sealed, so measure the Ze at the isolator.
Don’t forget to code the IP rating.

PEG · May 1, 2019

Hi,how are those dual-rate meters and time-clocks,configured?

Deleted member 26818 · May 1, 2019

Left hand meter feeds the top Time switch.
The left hand 4 pole isolator isolates the off peak feed from the time clock, and the normal rate feed from the meter.
Then there’s two T&Es from the 4 pole isolator going into the building.
Right hand meter feeds the bottom Time clock and the right hand 4 pole isolator.