Discharge lighting - contactor

[coopersim]

I have an old sun flood style discharge light that I'd like to control with a photo cell and mechanical timer, however the time states it requires a contactor when used with discharge lighting - this is not something I'm familiar with, could anyone advise what I require and how to connect this correctly please?

The timer I'm planning on using ia a Grasslin 24hour mechanical timer.

Thanks

 

[ban-all-sheds]

The timer switches the supply to the coil of the contactor, the contactor normally-open (N/O) terminals switch the supply to the load.

A contactor is a heavy duty relay, although I'd not be surprised to find that there is technically another difference which we can start to argue about.

 

[DaftPunk]

When looking at the rating of contactors it'll say something like:

20 (3) A

The first number is how much resistive load it can switch. The second number in brackets is how much inductive load it can switch.

SON floodlights and the like are inductive loads.

 

[AdrianUK]

I have an old sun flood style discharge light

Do you mean 'sun flood' or SON flood?

'sun flood' was a type of tungsten-halogen floodlight made by Thorn in the 1980's. It isn't/wasn't a discharge lamp.

 

[Robin0577]

A contactor is a heavy duty relay, although I'd not be surprised to find that there is technically another difference which we can start to argue about.

My understanding (which may well be flawed) is that to qualify as a contactor, rather than simply a mains rated relay, the device must have a >3mm contact gap when open, as is usually required for isolation purposes.
I suspect there may also be some requirement for it to be constructed in such a way that the contacts cannot weld shut provided that it's used within it's ratings.