Live cable indicator

[Vernonya]

I have a 30 gallon hot water tank in a cupboard. The switch to switch it on and off is inside the cupboard. I only use the water in the tank for washing up. But herein is the difficulty, I tend to forget that it is switched on and keeping a 30 gallon tank constantly hot unnecessarily is expensive. I do not own the property so I cannot interfere with the electrics. What I am trying to find is some kind of sensor device that goes around the cable leading from the switch to the tank. If the cable live ( this only happens if it is switched on, of course) then the sensor device could operate a led outside of the cupboard and I could then see, at a glance, if the tank is switched on, or off on the inside. There must be such devices, but I cannot identify what they are called,or who sells them. Your comments appreciated

 

[EFLImpudence]

Boil a kettle.

 

[Vernonya]

I understand that the objective here is to find out things one does not know, if you have nothing constructive, just childish remarks, use twitter

 

[rjm2k]

You could try one of those energy monitors but not sure it would work on two core wire rather than a meter tail.

 

[flameport]

You could try one of those energy monitors but not sure it would work on two core wire rather than a meter tail.

It won't work - such things only work on a single core wire as they measure the current flow. With L&N together, the net current flow is zero.

The answer is to move the switch outside the cupboard, and have one with a neon indicator in it - ask the landlord.
If they won't agree to move the switch, then it's the kettle option.

The device you want to fit on the cable with a remote indicator probably doesn't exist, as even if one could be made to work on a multiple core flex, almost no one would want such a thing. Relocating the switch is much easier and cheaper.

 

[A2018]

If there is no commercial product available then can you make something to do the job yourself ? Would it be possible to position a microswitch in such a way that the switch for the immersion heater moves the lever of the microswitch without the microswitch getting in the way of operating the immersion switch. If so its a simple circuit of a battery, led, resistor and the microswitch. With the microswitch stuck down with double sided sticky pads. If there is a neon indicator on the swich then you could always do a circuit using a light dependant resistor but that is a little more complicated.
Or go low tech and have a sign hung on the switch when you turn on the immersion heater hang the sign on the door when you turn off hang it back on the switch.

 

[PrenticeBoyofDerry]

I suggest you speak to your landlord regarding this, to resolve your issue would require some alteration to the hardwiring or flex to heating element, therefore the landlord needs to deal with it.
Or you need to get into a routine where you do check the isolation switch.

 

[plugwash]

even if one could be made to work on a multiple core flex

I'm quite sure such a thing could be made. You can buy clamp meters for multicore cables nowadays.

Whether there would be enough of a market to make it viable is another matter.

 

[bernardgreen]

The magnetic field around twin and earth is virtually zero when the current in the neutral is the same as that in the live, Being in opposite directions the magentic field around each wire cancel each other. That is how an RCD sensor detects leakage.

It is possible to detect current flow in twin and earth using a small open core sensor. This has to be placed as close to one conductor as possible so it is most affected by the field from that core and less affected by the field from the other core.

This will not measure current accurately but should be able to distinguish between no current and some current. It would not pick up enough energy to operate any type of indicator. Some form of amplifier would be needed.

Better results would be obained using two sensors, one on Live and the other on Neutral and adding their outputs.

This is not however a viable answer to the question the OP asked.

 

[rjm2k]

30 gallons is a lot for washing the pots anyway, boil the kettle

 

[Jackrae]

Or alternatively buy a simple battery operated kitchen alarm timer. Then, when you turn heater ON set timer to go off in say 15 minutes, or longer if you're heating for a bath/shower etc

 

[333rocky333]

maybe make something up using a battery alarm unit and a strap on cylinder stat as the contacts, so that it alarms at a certain temperature, reminding you to turn it off

 

[phatboy]

These seem like a goof solution?

http://www.tlc-direct.co.uk/Main_In...rs_Index/Immersion_Heater_Timers_2/index.html

This could just replace the current switch, as long as it doesn't have a fuse in it.

 

[kai]

Those timers can also be mounted alongside the existing switch too, gets round the problem of the fuse situation in the existing setups.

 

[Vernonya]

Many thanks for your replies, some are quite good and could be useful.
What I was really looking for is non invasive. To my thinking if its switched on, then there is current flowing. In that case a device which slips a coil around the wire which should give me an induced current in the coil. That would have to be rectified and could then light up an led where ever I wanted it . From your replies there seems to be no such device but other suggestions are worth a shot. I going to give the one about the timer device to the landlord, so far he has been unenthusiastic about move the switch