How Is A Time Clock Wired In A Consumer Unit To Operate Contactors To Control Mcbs For The Heating

WestMidsElectrical · Aug 19, 2016

Hi everyone, I'm very curious about economy 7 boards on electrical installations with time clock on din rail and the contactors. I have a photo to show exactly what I mean, now I want to know how does the time clock switch the contactor to allow the heaters to operate from economy 7 times, I do wire heating systems but would rather get expert advice regarding the consumer unit layout and wiring.

Appreciate if anyone could help!

[ElectriciansForums.net] How Is A Time Clock Wired In A Consumer Unit To Operate Contactors To Control Mcbs For The Heating

Leesparkykent · Aug 19, 2016

timer switches the coil of the contactor.

WestMidsElectrical · Aug 19, 2016

My point is what board is the mcb fed of, and what would be the layout of the outgoing side of the contactors in the picture, in that set up, I've worked with time clocks and contactors would say couple of times however not for heating just for car park lights on a contactor overrided by a photocell, sorry mate just very curious

WestMidsElectrical · Aug 19, 2016

I presume the idea is - economy 7 without the meter being a dual one and they installed a board with heaters with a time clock operating in the hours of economy 7 times and the it switches the contactor to make this work, thought it was clever installation but wanted more explanation and diagrams why,, I've saw the contactors used on pv installations but was quite confused the reasons behind it!

Richard Burns · Sep 1, 2016

The board is set up to switch on when the contactor operates.
The timer is set to operate within the Economy seven time periods and then switches the contactor coil.
The board is then powered up and the heaters will start to operate (assuming they are locally switched on).
When the Economy seven time stops the timer switches off and so powers down the coil of the contactor that then switches the board off.
This is a diagram of an internally switched arrangement in one board along with other 24hr circuits.
The timer and contactor coil are protected by a circuit breaker on the 24hr side.
The heaters circuit breakers are powered only when the contactor is on.