Electricians: On/off switch with live/dead indicator

Ildhund

I hope the subject is clear enough. 

We frequently see consumers with multi-rate metering arrangements advised to make sure that the switch that controls, say, the charging  power to a storage heater has a neon that lights up when the power is on. As far as I can see, this sort of switch only lights up if it's both on and the circuit it's connected to is live. 

I have asked without getting an adequate response whether it's possible to have a switch with an indicator that shows whether the circuit is live or not regardless of whether the switch is in the on or off position. This would tell me, for example, whether my E7 meter has switched the power to the offpeak heating circuit on or not. I could then decide to turn a different power-hungry appliance on knowing the electricity it consumed would be at the cheap rate until the light went out. It would be even more helpful for those on schemes with daytime offpeak slots like Economy 9 and 10. I suppose I'm thinking of something like the 'On air' lamp outside a broadcast studio to deter intruders. 

An alternative would be a little LED or something in the kitchen wired to the switched circuit. The problem with this is that this circuit's wiring is all hidden, with the equipment it powers hard-wired - no plug-and-socket. 

Any ideas from the sparkies out there? 

Gerry1

https://www.meteorelectrical.com/switches-and-sockets/switches-sockets/13a-fused-spur-with-neon-no-switch.html

Could be installed next to an NSH E7 outlet.

Scrounger

Ildhund said:

I hope the subject is clear enough. 

We frequently see consumers with multi-rate metering arrangements advised to make sure that the switch that controls, say, the charging  power to a storage heater has a neon that lights up when the power is on. As far as I can see, this sort of switch only lights up if it's both on and the circuit it's connected to is live. 

I have asked without getting an adequate response whether it's possible to have a switch with an indicator that shows whether the circuit is live or not regardless of whether the switch is in the on or off position.

Slightly unorthodox solution but if you transpose the input and output connections on your conventional 20A mains switch with neon (or fused connection unit with neon), that would achieve this effect.

I've noticed this effect when these switches or fused outlets have been incorrectly wired (neon is always on when circuit powered).

If using a FCU, be careful when removing the fuse if circuit is powered as it will be live (regardless of switch position).  In this regard, the 20A switch (no fuse) would be a safer option.


Scrounger

Ildhund

Gerry1 said:

Could be installed next to an NSH E7 outlet.

Thanks. That looks like what I was hoping to find, but ... I can't go digging holes in my landlord's wall to install stuff. It would probably invalidate the incredibly thorough EICR he commissioned at enormous expense last year    It might be helpful for someone about to install a new NSH system, but then a doctored switch à la Scrounger would be an obvious choice in that situation.

QrizB

It looks like there's room in the faceplate of the switched fused spur that @Gerry1 posted for a competent person to drill the faceplate and fit a second neon. This could show the status of the circuit, rather than of the spur.

Scrounger

Ildhund said:

Gerry1 said:

Could be installed next to an NSH E7 outlet.

... I can't go digging holes in my landlord's wall to install stuff.

   You could attach one of these to the E7 outlet:

Non-Contact Voltage Detector Pen

Ildhund

QrizB said:

... a competent person to drill the faceplate and fit a second neon. 

That rules me out, then

Ildhund

Scrounger said:

... transpose the input and output connections on your conventional 20A mains switch with neon (or fused connection unit with neon), that would achieve this effect.

I've noticed this effect when these switches or fused outlets have been incorrectly wired (neon is always on when circuit powered).

Thanks. This looks like what happened with my electric shower's ceiling pull switch. A new one was installed*, and I noticed that its neon was always lit if the switch outside the bathroom (which I'd never noticed before) was on. Prior to that, the neon only lit up when I pulled the chain. Now I see that there's a mechanical red indicator (like the vacant/engaged signal on the door of a public toilet) on the pull switch. So now it's probably acting as intended, whereas it wasn't before. 
  

*   [OT]
The shower had just stopped working, so the landlord sent his man around to install a new one. After having drilled several new holes in the tiles because the mounting screws for the new one didn't match the existing holes, he got it up on the wall, plumbed in and wired up. Pulled the chain and - nothing. That's when he dismantled the pull switch and found the havoc wreaked, probably by small animals in the attic feeding on cable insulation tugging wires out. Result: a slightly red face, another trip to TLC to buy a new switch, a working shower and a promise from me not to tell the landlord about his faux pas. 

FreeBear

Ildhund said:

Gerry1 said:

Could be installed next to an NSH E7 outlet.

Thanks. That looks like what I was hoping to find, but ... I can't go digging holes in my landlord's wall to install stuff. It would probably invalidate the incredibly thorough EICR he commissioned at enormous expense last year    It might be helpful for someone about to install a new NSH system, but then a doctored switch à la Scrounger would be an obvious choice in that situation.

Installing a switch as per Scrounger's suggestion would probably trigger a fail on the next EICR and is dangerous. The neon is there to indicate the state of the switched load !

Fortunately, you can get indicator lights in various colours, and it wouldn't be too difficult to drill a hole in a faceplate for one.

Scrounger

FreeBear said:

Ildhund said:

Gerry1 said:

Could be installed next to an NSH E7 outlet.

Thanks. That looks like what I was hoping to find, but ... I can't go digging holes in my landlord's wall to install stuff. It would probably invalidate the incredibly thorough EICR he commissioned at enormous expense last year    It might be helpful for someone about to install a new NSH system, but then a doctored switch à la Scrounger would be an obvious choice in that situation.

Installing a switch as per Scrounger's suggestion would probably trigger a fail on the next EICR and is dangerous. The neon is there to indicate the state of the switched load !

I was merely offering a possible solution to this question: Ildhund said:

I have asked without getting an adequate response whether it's possible to have a switch with an indicator that shows whether the circuit is live or not regardless of whether the switch is in the on or off position. 

IMO my solution isn't particularly dangerous and the op would be familiar with its operation.  Most switches and outlets don't even have the luxury of a neon indicator - are these unsafe?

Saying that, its not something I would use myself as I prefer the conventional use of the neon (on when power to the load).


Scrounger




  

tacpot12

Ildhund said:

QrizB said:

... a competent person to drill the faceplate and fit a second neon. 

That rules me out, then

It's really very simple. I fitted one of these 9m Neon Indicators to a faceplate recently: https://www.ebay.co.uk/itm/294665774483

If there is any uncertainty about what the indicator is indicating, just add a label.