R1+R2 Readings - Advice

[mr2pep]

Hi,

Hoping someone can help.

I went to a job today where the householder had sixteen downlights installed less than twelve months ago, (no test sheet or certificate for the install), the complaint being that bulbs (240V GU10) are always blowing. I pulled the downlights and checked connections, all seem ok.

The downlights are split in to two circuits of eight and a central pendant. Controlled by two three gang, two way switches, one lot of eight is wired one way and the other eight and pendant are wired two way.

So I did a R1+R2 test on the eight downlight two way circuit, with the switches closed I got a reading of 1.2 ohms and switches open a reading of >1999 ohms. However without moving the meter or leads I flicked the switches on the two other circuits and redid the test and got readings of 53.4 ohms and 23.2 ohms, surely the other two switches should not interfere and I should still have got readings of >1999?

Am I correct in that reasoning? Or am I an idiot and missing something?

Regards, Paul.

 

[SirKit Breaker]

I cant really fully understand what you are asking, but i dont think you are an idiot, but you may be missing something. the biggest cause of blown GU10's is because people change them with their fingers, this causes hotspots, and the lamps go pop. Another reason is the use of cheap nasty lamps. My advice, put the tester away, and tell client that new clean lamps ned fitting. GU10's are expensive to run, so suggest they take a one time hit and fit LED. I have had my 240v LED's in the bathroom for 3 years, still on original lamps, and before anyone jumps in YES they are IP rated for the zone they are in.

Cheers.......Howard

 

[chrish_1977]

The other thing to check is some lamps are designed to "throw" the heat up or down, if you fit the wrong lamps then this may cause them to overheat and blow too,

 

[telectrix]

i'm with howard. cheap lamps. price him up for LEDs, explain the saving in lamp changes and leccy bill.

 

[yellowvanman]

Dimmers also help - gives a 'soft start'

 

[mr2pep]

Cheers, for the input. Taken on board. Hopefully one day be able to return advice.

 

[pete555]

Hi,

Hoping someone can help.

I went to a job today where the householder had sixteen downlights installed less than twelve months ago, (no test sheet or certificate for the install), the complaint being that bulbs (240V GU10) are always blowing. I pulled the downlights and checked connections, all seem ok.

The downlights are split in to two circuits of eight and a central pendant. Controlled by two three gang, two way switches, one lot of eight is wired one way and the other eight and pendant are wired two way.

So I did a R1+R2 test on the eight downlight two way circuit, with the switches closed I got a reading of 1.2 ohms and switches open a reading of >1999 ohms. However without moving the meter or leads I flicked the switches on the two other circuits and redid the test and got readings of 53.4 ohms and 23.2 ohms, surely the other two switches should not interfere and I should still have got readings of >1999?

Am I correct in that reasoning? Or am I an idiot and missing something?

Regards, Paul.

Lamps not bulbs what are they tulips

 

[SirKit Breaker]

Cheers, for the input. Taken on board. Hopefully one day be able to return advice.

No probs matey, dont forget the thanks and like buttons

 

[applemac]

The other thing to check is some lamps are designed to "throw" the heat up or down, if you fit the wrong lamps then this may cause them to overheat and blow too,

aluminium reflectors