luminaries in explosive atmosphere

[john h owen]

When doing a IR test on a 230v circuit containg several explosive (Ex) proof luminaries:-

1)Voltage to be applied
2)Reason why the switch controlling the luminaries is left in the off position

 

[malcolmsanford]

Where are you conducting these tests? Are the luminaires in a quarry or mine or in a potential explosive enviroment.

Intrinsically safe insulation and continuity testers must be used for these tests and the chances are where your going to test them will be beyond the remit of the BS 7671-2008 and will come under a licencing authority.

Also the chances are you will need COMPEX certification to work on the installation.

Is this a general question or are you going to carry out testing

 

[swparksey]

You need to know the method or protection, Ex Ib Ex ia or Ex d etc, before considering how to test them, this then relates to your question 2, switch on or off, any how you would have to remove the lamps.

As for COMPEX, only if the client requires it.

Loads of the stuff I see is explosion proof, and testing can be problematic, most of the time it is done with a Low Resistance Ohm Meter, but even this introduces problems if the protection method is Ex ia and barriers are used.

Good luck

 

[Graeme Harrold]

What the OP said, sounds more like an exam question rather than veing job specific......

 

[malcolmsanford]

What the OP said, sounds more like an exam question rather than veing job specific......

Yes agree which is why I asked if it was a general question or an actual test.

 

[john h owen]

Where are you conducting these tests? Are the luminaires in a quarry or mine or in a potential explosive enviroment.

Intrinsically safe insulation and continuity testers must be used for these tests and the chances are where your going to test them will be beyond the remit of the BS 7671-2008 and will come under a licencing authority.

Also the chances are you will need COMPEX certification to work on the installation.

Is this a general question or are you going to carry out testing

Hi its a 2391 exam question taking it as the explosive proof luninaires with the switch in the off position are in an explosive atmosphere.

 

[swparksey]

Nice question Vague as can be, my answer would be.

1. Insulation testing should be carried out using intrinsically safe test apparatus at 500v DC. Even when using such apparatus, there may be a possibility of incendive sparking therefore the area concerned must me purged and non hazardous.

2. Prior to undertaking low voltage insulation tests, equipment that may be damaged by such tests must be isolated.

 

[malcolmsanford]

God that 2391-10 is getting more obscure with their questions.

Well like all city and guilds questions they tend to dress up what is a logical question and answer in a bit of dressing. I haven't got the GN 3 with me but I can't remember anything in it about explosive atmospheres and the 2391-10 is based on the GN 3. Unless your doing the 2391-20 !!

So I maybe way off here and will get a compex sparks writing in telling me I'm talking rubbish. So going for the obvious

1. Voltage would be 500v DC as per normal 230 system, but using those special Intrinsically safe insulation resistance tester
2. Reason you testing to the switch only is that your unable to disconnect the lamp/ballast/ etc so your testing with switch off. As you unable to disconnect vulnerable equipment under test, which will be noted on your PIR as it should be that test.

If i'm wrong I'm sure someone will come back to me and if i'am sorry to mislead you lol