Mechanical timer for DP 20A

[Jimmy Lau]

I tried to install greenbrook mechanical timer for my cylinder water boiler. I found it currently fitted with double poles 20A. Do you think it will work and here comes the spec as attached

 

[JohnD]

I tried to install greenbrook mechanical timer for my cylinder water boiler. I found it currently fitted with double poles 20A. Do you think it will work and here comes the spec as attached

When you say water boiler, do you mean a hot water cylinder?

Does it have a 16amp immersion heater?

 

[Jimmy Lau]

Yup is hot water cylinder. Around 2kW

 

[JohnD]

Immersion heaters are usually 3kW.

You can use that timer

Fit it downstream of the DP switch.

 

[Jimmy Lau]

You mean I need to keep my DP switch and fit this as extension, instead of replacing it?

 

[JohnD]

Yes

 

[Jimmy Lau]

Can I just replace it? Will it cause electric issues?

 

[JohnD]

It would mean you don't have DP isolation, which is strongly preferred during repair or replacement.

When the immersion heater goes faulty, you may be unable to stop it constantly tripping the RCD.

Why do you want to?

 

[Taylortwocities]

Yup is hot water cylinder. Around 2kW

2kW is about 9 amps. So a 16AMP supply is not necessary. Think you need to confirm the ACTUAL spec before we go any further.

 

[Jimmy Lau]

My direct copper cylinder is connected with 'MK LOGIC PLUS 20A 1-GANG DP CONTROL SWITCH WHITE WITH NEON'. And tried to replace that with 'Greenbrook t100a-scr mechanical timer'. My main intention is to have a timer to control when to switch on and off. Ideally, replace the switch, so I can use that location to install 'Greenbrook t100a-scr mechanical timer'. I just attached the current connection. And I draw my plan. Do you think this will work? And will it cause any issues?

MK Logic Plus 20A 1-Gang DP Control Switch White with Neon - Screwfix

Order online at Screwfix.com. Double pole switch with flex outlet in the base and neon locator. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

Greenbrook T100A-SCR Mechanical Timer - Screwfix

Order online at Screwfix.com. 230V / 16(2)A. Ideal for most heating applications. Features timer 'On' status indicator. Fits a 25mm dual appliance socket box should it be required to mount the timer next to a fused spur or socket outlet. Suitable for any 25mm deep socket box fitted with an earth...

www.screwfix.com

 

[Jimmy Lau]

It would mean you don't have DP isolation, which is stronger preferred during repair or replacement.

When the immersion heater goes faulty, you may be unable to stop it constantly tripping the RCD.

Why do you want to?

Sorry, I confuse here. Do you mean the current 'MK LOGIC PLUS 20A 1-GANG DP CONTROL SWITCH WHITE WITH NEON' provide DP isolation? If I replace that with 'Greenbrook timer', I will lose DP isolation. Do you think it still work? Will it cause any electrical issues? I thought it goes faulty, I just need to remove the RCD for repair?

 

[JohnD]

Do you mean the current 'MK LOGIC PLUS 20A 1-GANG DP CONTROL SWITCH WHITE WITH NEON' provide DP isolation?

Yes

If I replace that with 'Greenbrook timer', I will lose DP isolation.

Yes

Will it cause any electrical issues? I thought it goes faulty, I just need to remove the RCD for repair?

It will be the immersion heater that in time, will go faulty. And eventually the timer will wear out. It is very preferable to have DP isolation before starting repair.

All you have to do is drill two holes in the wall and screw on an extra plastic backbox.

60pence

1-Gang Surface Pattress Back Box 25mm - Screwfix

Order online at Screwfix.com. Moulded box. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

 

[Taylortwocities]

Nice photos. But you still have not provided the ACTUAL specification for the immersion itself. It may be written on the cap that covers the immersion, or on the end of the element itself.

 

[Jimmy Lau]

Nice photos. But you still have not provided the ACTUAL specification for the immersion itself. It may be written on the cap that covers the immersion, or on the end of the element itself.

Here comes the actual specs of the immersion as attached
3kW 240V, 2.76kW 230V
Type-BS311C

Thanks

 

[Taylortwocities]

13amp.