Plug-in Single Pole circuit breakers with timers?

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jordandalley

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#295532 4-Apr-2022 16:22

I'm currently on Electric Kiwi on their Movemaster plan which has cheaper off-peak power, and the hour of free power each night at 9pm.

I'm renting a house and want to find a way to put a timer on the hot water cylinder that basically stops it from heating during on-peak.

The switchboard in the house uses those old-style porcelain fuses - some of which have been replaced by those plug-in style circuit breakers.

I've been looking around and was hoping I could find a plug-in MCB that had a timer functionality, but I've come up short. The rest of the hot water system is completely hard-wired, so not sure how I can address this.

Any solutions that doesn't involve an electrician or involving the real estate? :)

Chur! :)

richms

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#2896864 4-Apr-2022 16:42

You wont find one because its such a minor use case to replace those with something that noone would bother to make one, and it would need a neutral connection as well so cant be plug in. Possibly someone could make one with an external DC supply or battery, but again, whats the market for it vs the compliance costs?

There are plenty of din rail mount timers from legit brands which is how it should be done on installs now, and making things to cater to legacy probably unsafe installations would have no demand.

Richard rich.ms

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gregmcc

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#2896877 4-Apr-2022 17:15

no such beast exists, option would to install a timer on your fuse board, but 2 problems, this is not something a homeowner is allowed to do (work on any switchboard), and most timers are 10A contacts, your H/W could easily be 10A if not more and would burn out the timer. You need to get an electrician involved.

Jase2985

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#2896878 4-Apr-2022 17:18

this isnt the solution for your situation but i was looking at these yesterday. designed for newer DIN rail circuit boards.

https://corysadvantage.co.nz/products/product/0000441525

https://www.sparkydirect.com.au/p/Hager-EH010-Single-pole-timer-24-hour-16-4-amp-Analogue-No-Back-up-Battery

gregmcc

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#2896882 4-Apr-2022 17:22

Jase2985:

this isnt the solution for your situation but i was looking at these yesterday. designed for newer DIN rail circuit boards.

https://corysadvantage.co.nz/products/product/0000441525

https://www.sparkydirect.com.au/p/Hager-EH010-Single-pole-timer-24-hour-16-4-amp-Analogue-No-Back-up-Battery

Both of these may seem like they will work, but from past exp. they will end up cooking. They claim a 16A load capacity, but it's the making and breaking capacity that cooks them. I would be installing a 20A contactor driven from the timer.

jordandalley

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#2896886 4-Apr-2022 17:34

Thanks for the replies everyone. Sounds to me like I am sh*t out of luck! :P

SomeoneSomewhere

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#2896933 4-Apr-2022 20:31

We had a similar timer (16A rated Grasslin) running the 3kW HWC for probably about 20 years, working fine. Now replaced by a PLC with a contactor. HWC elements are resistive loads and should be pretty easy on the contacts.

It might help that it probably almost never broke the current as it always ran long enough (overnight) to fully heat the cylinder and have the thermostat switch it off.

elbrownos

107 posts

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#2897079 5-Apr-2022 09:31

I installed a Sonoff TH16 between the HWC switch and the cylinder.

It's not exactly compliant but I'm comfortable with the risk.

pipe60

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#2897418 6-Apr-2022 08:45

I use solid state relays with zero crossing switching for HW switching off my house PLC, no problems so far.

timmmay

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#2897423 6-Apr-2022 08:58

I simply hired an electrican to do this with my old style fuse board (now replaced). They supplied a digital timer (which from memory was 16A switching), I think it cost about $250 parts and labor five years ago. It'd probably cost more now.

elbrownos:

I installed a Sonoff TH16 between the HWC switch and the cylinder.

It's not exactly compliant but I'm comfortable with the risk.

If it burns your house down will insurance cover you for non-consented work? Maybe not. You may have saved $300 but it could cost you $750,000 if your house burns down and your insurance refused to pay because of it.