mains switched contactor/relay in a box

[sandy771]

Hi

I am helping with some village lights and need some advice as to a route forward (our electrician is unavailable for an undefined period)

We currently have 7 lights strings, each is fed from a 13A socket via a mechanical timer that sits between the plug and the socket. Each timer needs to be adjusted every few weeks to take into account the changing time of sunset. The timers are not very accurate so the different light strings come on over a 20 minute period.

We have some radio link switches that we want to use to control each light string from, so the master transmitter will be plugged into one timer, and all slave strings will turn on/off when the transmitter turns on/off. This has been tested and will work.

The problem is that the radio receivers are only rated for 4A and the light strings require about 10A. The solution I understand is to put a contactor in a consumer unit and switch the contactor with the radio link receiver. This is problematic for a number of reasons including poor availability of our electrician and lack of 'slots' in consumer units.

I am looking for other suggestions as to how we can do this with minimal work

I wondered whether we could get (if it exists) something like a contactor in a box, i.e. a box that has a three pin plug input and socket output to supplythe 10A, that is controlled by a second 230V source (the 4A 4radio link).

Hopefully this makes sense

Any other suggestions greatfully received

 

[Gurnatronics]

What is the distance from Lights to the switching point? The easiest way to do it would be with quintic switches. You can get 13A through sockets with built in Radio receivers. 80m (roughly) outdoor range

Quinetic 13A Socket Adaptor Receiver | Quinetic (QUA313)

only problem would be they would require a manual switching, there is no transmitter that I know of that could be wired into a timer. You can get one switch that would pair to all the light strings.

Quinetic 1 Gang Wireless Switch - White - IP67 | Quinetic (QUWS1W)

all of the above need no wiring from an electrician, but is not automatic or timer

 

[sandy771]

Thank you for your reply.

Although all receivers are line of sight of the transmitter the furthest is about 500m. The radio links we have were tested across this distance and work OK.

 

[Lucien Nunes]

I wondered whether we could get (if it exists) something like a contactor in a box, i.e. a box that has a three pin plug input and socket output to supplythe 10A, that is controlled by a second 230V source (the 4A 4radio link).

Yes, this is how I would do it. There is no need to tinker with consumer units. You can mount a contactor or high-current relay in a box and control it with the output of the receiver. A convenient method would be to use a 2-module DIN-rail enclosure fitted with with a 1- or 2-module 16A DIN-rail mounting contactor that has a 230V coil. Three 16mm cable glands would let three cables into the box:

• Power feed from a 13A plug to the contactor contacts in 1.5sqmm
• Output from contactor contacts to a trailing 13A socket for the lights, in 1.5sqmm
• Control input from a second 13A plug (plugged into the receiver) to the contactor coil, in any size, 0.75sqmm fine.

Each unit would cost in the order of £30 and less than an hour to make up.

 

[sandy771]

That's great thank you.

Are there any issues with heat dissipation in a sealed IP66 box. We already have some 20A 2 pole contactors and the installation notes say that a 9mm spacer must be placed each side for air flow. I imagine heat would only be an issue of they are switched often, which wont be the case - on and off once evrey 24 hours.

Need to check to see what the current draw for a light string is so I can see if we can hang a double socket off this - which would simplify things.

 

[Lucien Nunes]

The heat is dissipated all the time the contactor is energised. One contactor in a box will be fine, spacers are needed when multiple units are mountedin a line on a rail.

 

[sandy771]

OK thank you - understood