[Mr Pothead]

Electrical & safety How do I convert watts to amps and amps to watts?

The formula for converting Watts to Amps is : Watts = Amps * Volts .
The formula for converting Amps to Watts is : Amps = Watts / Volts .

SAFTEY WARNING : Only use 80% of the circuit breaker capacity! .

Common Conversions North American and other 110 volt countries .
Lights : 1000W / 110V = 9.1A 600W / 110V = 5.4A 400W / 110V = 3.6A 250W / 110V = 2.3A
Circuits : 10A * 110V = 1100W and 80% safe usage is 880W 15A * 110V = 1650W and 80% safe usage is 1320W 25A * 110V = 2750W and 80% safe usage is 2200W 30A * 110V = 3300W and 80% safe usage is 2640W

Common Conversions British Commonwealth and other 240 volt countries
Lights : 1000W / 240V = 4.1A 600W / 240V = 2.5A 400W / 240V = 1.7A 250W / 240V = 1.1A
Circuits : 10A * 240V = 2400W and 80% safe usage is 1920W 15A * 240V = 3600W and 80% safe usage is 2880W 25A * 240V = 6000W and 80% safe usage is 4800W 30A * 240V = 7200W and 80% safe usage is 5760W

Remember that a circuit services more than one power outlet. A two outlet wall plug will use only one circuit. There will be more outlets on 240V systems per circuit than there will be in 110V systems.

Why has my timer switch failed and what should I do? Normal household timers are not designed or rated to deal with the inductive power load used by horticultural lighting. Go to your local Hydro shop and buy a contactor relay like this one. A contact relay switch is required so that the timer turns on the contactor which then turns the light on.

Almost all new growers will experience this failure. The reason for this is the contacts in these timers are not sufficient for the job. Household timers are rated for a RESISTIVE load, ballasts present an INDUCTIVE load, (a very large surge at switch on) this fuses the timer contacts together = Timer failure.

What is a relay switch? .......
An electro mechanically operated switch. Contact relay.

How safe are Mh and hps lights?
Many people have used these lights in their homes with no problems what so ever for thousands of hours. Good safety measures and common sense are to have smoke alarms inside and just outside of your grow area. Especially if your grow area is in your basement have a smoke alarm positioned so you will be able to hear it from the upstairs bedroom.


No1 Rule: Safety!