Do I need a relay?
- Herbal Hunter
- Posts: 67
- Joined: Sun 26th Apr 2009 07:20 pm
- Location: U.K.
Do I need a relay?
Hi people! Do I need a contactor/relay to go with my light or is that just for timers that cant handle the wattage of the light normally? Coz I can see why internet sites would have to sell u another product to go with their shitty timers that cant handle more than 300w, but ive got some digital ones that can handle bout 3000watts so can i plug my light straight into that or is a relay a must? Thankyou! 
- Rez
- Posts: 1363
- Joined: Sun 12th Feb 2006 02:01 pm
- Location: * Amsterdam * 27/28 Oct 2012
- DaveS
- Posts: 535
- Joined: Sun 26th Nov 2006 02:30 pm
- Location: UK
It's not the power handling you need to consider with these timers, it's the surge when the HID's power up that kills cheap timers.
You see, when the lights first turn on, they draw a huge amount of power to "fire up" the lamps, and with timers that aren't equipped to take this initial surge (i.e. ones that do not have a relay built in), you can end up with;
a) At best, a burnt out timer that will screw up the delicate light cycle of your plants...
b) At worst, a fire that will definitely screw up the delicate light cycle of your plants, AND will leave you homeless, in jail or in a coffin (delete as applicable).
Get a relay.
I use bog-standard B&Q type cheapo "3 for a tenner" style timers, but with a contactor/relay feeding them, I haven't had one fail in over ten years. Plus, I sleep at nights, knowing everything is safe.

You see, when the lights first turn on, they draw a huge amount of power to "fire up" the lamps, and with timers that aren't equipped to take this initial surge (i.e. ones that do not have a relay built in), you can end up with;
a) At best, a burnt out timer that will screw up the delicate light cycle of your plants...
b) At worst, a fire that will definitely screw up the delicate light cycle of your plants, AND will leave you homeless, in jail or in a coffin (delete as applicable).
Get a relay.
I use bog-standard B&Q type cheapo "3 for a tenner" style timers, but with a contactor/relay feeding them, I haven't had one fail in over ten years. Plus, I sleep at nights, knowing everything is safe.
- USbongLord
- Posts: 6704
- Joined: Tue 19th Sep 2006 07:47 pm
- Location: Baltimore,Amsterdam
this is what i do for a living,,,a contactor is always a good idea for multiple lights on a timer,,,a 3000 watt timer wont give you any probs if used with one light....now,,saying this,uk power runs a bit diff then us power...but one timer,one light,never a prob...have a great grow
rockin into the night