Extension Reel used with Smart Plug

Section62

FaceHead said:

Back the the original question: yes not a problem - think of it just like a normal switch that you can flick via WiFi. 

It isn't though.

A 'normal' switch is mechanical, with a minimum separation between contacts, and a mechanism which means the switch will remain in the current state until there is direct force intentionally applied by (usually) a human being.

'Plug in' switches such as timers and remote controls can't be guaranteed to have mechanical contacts with minimum separation.  Although we'd all hope they were designed to 'fail safe', most of the time we have no idea whether or not this is the case.

They have to be treated as if they have a mind of their own and could switch the power on at any moment in time with no human involvement whatsoever.

From a safety perspective that is totally removed from being anything like a 'normal' switch.

neilmcl

Section62 said:

Thready said:

It is in the conservatory and the reason for the remote plug is access.  the socket is behine the washer and drier and I have to be a contotionist to reach the switch to turn it off and as I am no longet in the first flush of youth that is becoming harder every year, a remote plug seemed to be the ideal solution, I just wanted to double check the safety.

There are three reasons why I wouldn't do this.

1) Electronics can fail.  For safety you always need to have a situation where you can quickly cut the power to electronic devices. Plugging something in to a socket without easy access means in an emergency you wouldn't be able to switch it off, without isolating the whole circuit at the consumer unit.  Also, being in a hidden location means you wouldn't see some of the warning signs of imminent failure, such as scorching or yellowing from overheating.

2) The safety risk is not limited to electronics failing.  If the extension lead is being used outdoors there is an increased risk of accidents and damage.  Being able to safely isolate the extension lead quickly and completely could be critical to saving someone's life.  The plug being inaccessible means this isn't possible (unless again, by isolating at the consumer unit).  You can't rely on an electronic switch to completely disconnect the extension lead from the mains supply.

3) For outdoor use (especially with a lawnmower) it is essential to use an appropriate RCD.  If you use a plug-in one - highly recommended when using power tools outside - then you will be in the same position of having the RCD in a location which isn't accessible if it needs to be reset, or if it fails.


It would be much safer to get an electrician to fit an additional socket in a position which is easily accessible.  And if the washer / drier are also plugged into inaccessible socket(s) then this is all the more reason to do the job properly and have sockets installed in better positions as washing machines and tumble driers are also appliances which should have an accessible means of isolating in case of emergency.

Maybe there are other locations/appliances in the house connected to inconvenient sockets and it would be worthwhile thinking about doing something about these at the same time as well?


In any event, adding a remote plug adds things that can go wrong over and above having a standard extension cable left permanently plugged in and switched on.  It doesn't really improve safety, and arguably makes things worse in some situations.

These were my thoughts/concerns exactly.

Myser

The extension reel probably has a thermal cut-out in it (check for a reset button).

If there is a fault and the cut-out, MCB or RCD does not trip, you can isolate the circuit at the consumer unit in an emergency.  The risk is very low as most garden tools are double insulated.

So long as the reel is connected to an RCD, you'll be fine.  If it's a plug-in RCD then you'll need access to the socket anyway to reset the RCD when you switch power to the socket back on.

If you want the convenience of a smart socket outdoors, sockets like this are available:

https://tech-planet.co.uk/Smart-Switch/Ener-J-Smart-Wifi-Double-Outdoor-Socket/

or BG have one with a WiFi extender built-in:

https://www.bgelectrical.uk/wiring-devices/weatherproof-accessories/weatherproof-wifi-range-extender

Section62

Myser said:

If there is a fault and the cut-out, MCB or RCD does not trip, you can isolate the circuit at the consumer unit in an emergency.

If something doesn't 'trip', then how would the user be aware of a fault which requires them to go and hunt for the consumer unit - and then work out the correct breaker to operate - in a situation which required an emergency response?

This is why having access to the plug is so important.  If something does go wrong - which isn't a fault which is dealt with automatically - then it needs to be seen, and dealt with promptly.

Which means not putting things that can go wrong in places where they can't be seen, and providing for a quick means of disconnection which is intuitive, rather than needing some knowledge of how electrical systems work.

Myser said:

The risk is very low as most garden tools are double insulated.

 

Using mains electricity outdoors is inherently risky and double insulation only partially mitigates the increased risks.

Furthermore, double insulation of garden tools does nothing to reduce the risk posed by damaged or cut cables and leads.

grumbler

Why not just to make a proper outdoor socket? It costs a tenner and can be wired with a flexible cable going though a wall an plugged into the very same socket inside or some other (like an extension lead going through a wall)

This is providing that all your sockets are RCD-protected.

Myser

Section62 said:

Which means not putting things that can go wrong in places where they can't be seen, and providing for a quick means of disconnection which is intuitive, rather than needing some knowledge of how electrical systems work.

Having a quick means of disconnection is terminology often used in relation to machinery in industrial applications. The overuse of isolation switches that you see above kitchen counter tops are unnecessary and often added due to misinterpretation of the regulations (537.3.3). Your post comes across as scaremongering.

This page may help clarify and yes, unswitched sockets are still available:

https://www.dses.co.uk/index.php/free-advice/105-mythbustin

@Thready has said that they are going to plug a lawn mower into the reel in the summer which has its own safety switch in the handle! There is more chance of a plug socket switch failing than the garden tool switch due to safety testing. The question of a fault in the garden tool electronics is therefore moot.

Section62 said:

Furthermore, double insulation of garden tools does nothing to reduce the risk posed by damaged or cut cables and leads.

Neither will a switched socket, which is why I and others mentioned an RCD in our posts.