Use RCD as on/off switch

[hillwalker01]

Is it permissible to use the reset + test buttons of an RCD plug adapter as on/off buttons for a 10A load?

I have a 2000W power saw which I want to switch on and off at the socket under load, ie. the tool's own switch will be permanently on. (The details are un-important.)

I have an extension cable with unswitched sockets, and want to use an RCD for safety. I don't really want to add a third component in the form of a switched multi socket adapter, and in any case like the idea of quick, colour-coded push-buttons to operate the saw.

Are the reset & test buttons suitable for such load switching?

 

[Strima]

No as they are designed as test switches and not for functional switching. They would fail eventually, probably quite quickly with a 10 amp load.

 

[pc1966]

As above, a 2kW power saw will have a high inrush current so it will quickly burn the RCD contacts out.

Ideally you are looking for a "Direct On Line" starter such as this:
https://uk.rs-online.com/web/p/dol-star-delta-starters/9094079/

Most 3-phase starters can be wired for single phase, they are basically a 3-pole contactor and start/stop buttons to allow the windings of the contactor the be energised and de-energised. Also they release automatically on power fail, so it the mains returns after a fault the motor does not burst in to life!

 

[pc1966]

Also if you are bying a "3 phase" starter it has to be rated at 6kW or more for your 2kW motor as they give the rating when running on 3-phase.

 

[telectrix]

change the extension lead for one with switched outlets. if a switch on that fails, it's a cheap replacement.

 

[hillwalker01]

Thanks for the advice, I'll probably go with a regular switched outlet as the direct online starter is probably overkill for the occasional use this will be put to.

Thanks

 

[Mike Johnson]

Why isn't the saw fitted with a No Volt Release switch already? You have not said if this is Three Phase, but everyone else has, is it?

https://www.ebay.co.uk/itm/283335769207

 

[hillwalker01]

No, it's single phase. Thanks for that link - an NVR switch is clearly exactly what I need!!

 

[Mike Johnson]

The good thing about an NVR is they switch off automatically if you get a power failure, in as a trip of the MCB or RCD, so when you switch the power back on the unit does not start up by itself, you have to reset the switch, I have them on all my large workshop tools, even the extractor.