Lights Blow After 5-6 Weeks

[Spark123]

Arcing can cause RCDs to trip - not sure how it happens but it does.

Set your multimeter to volts AC ~.
.
.
.
Note the voltage may display negative, if you have your probes reversed.

Poor Crafty - the AC supply in this country changes direction 100 times per second going positive 50 times and negative 50 times, up to 340v ish and down to -340v ish, the RMS value of which is 240v (using true readings).
It doesn't matter which way around you connect your probes on AC - the normal value which is read is the RMS.

 

[bernardgreen]

Does crafty have the mental capacity to work out the theoretical reason ?

 

[Spark123]

I can't remember myself how to do that - seem to remember it is something to do with integration!
Short cut is peak x 1/root2 = RMS (root mean squared)

 

[Steve]

OK OK OK I'll go back into my corner. Naff orrf the lorra ya!

 

[ban-all-sheds]

Poor Crafty.

Crafty?

 

[RF Lighting]

Many moons ago, Steve used to be known as crafty1289, and then just crafty when he got upset at us making fun of him being 14 years old

 

[stuartsjg]

The UK mains can go up to 254v maximum average but shorter term averages are allowed.

I've seen many bulbs being rated at 220v for sale in the uk!

A general rule is a 5% change in voltage yields:
- halving or doubling the lamp life
- a 15% change in luminous flux
- an 8% change in power
- a 3% change in current
- a 2% change in color temperature

So a 220v lamp quoted at 6000H running at 253V (+15%) will last 750h.
(6000 / 2 = 3000, 3000 / 2 = 1500, 1500 / 2 = 750)

If your not happy using a multimeter, buy one of these plug in energy meters and they will tell you the voltage.

Quite often if you are at the end of a long cable on your street, at times of low load the voltage will rise allot, and at high load will fall.

Same problem if you are close to the supply transformer, you will always have a high voltage!

Find out the voltage, let us know and that will answer allot of questions.

Stuart