Ir testing on bus bar track

[Farmelectrics]

Been doing pir testing on commercial building been shorting out ln and testing to earth. Been getting readings of 5 to 8 m ohms on some of the tracks i no this is an acceptable reading but i was wondering to may be make the client aware of the low readings or just leave it. Personally if it was my responsibly i would advise to lift flooring unplug every device thats plugged into the track and re test l n l e n e this would be very time consuming and also very costly any thoughts or advise would be much appreciated . This is an on-line shopping company and if they did loose power to pcs it would be very costly to the company

 

[Engineer54]

Unless the underfloor void has some form of air forced air flow, then i would put your IR reading down to natural underfloor humidity levels. Not much you can really do about that unfortunately, there are some really badly designed raised floor installations out there, and anything that has been installed in those voids suffer for it!! ...lol!!

 

[IQ Electrical]

Been doing pir testing on commercial building been shorting out ln and testing to earth. Been getting readings of 5 to 8 m ohms on some of the tracks i no this is an acceptable reading but i was wondering to may be make the client aware of the low readings or just leave it. Personally if it was my responsibly i would advise to lift flooring unplug every device thats plugged into the track and re test l n l e n e this would be very time consuming and also very costly any thoughts or advise would be much appreciated . This is an on-line shopping company and if they did loose power to pcs it would be very costly to the company

You're talking between 5 and 8 Million Ohms! and that is probably not a true reading, you are implying that you are testing with items of current using equipment 'plugged in' and even though you are doing L+N combined to E you will still be measuring any leakages on the equipment.

 

[Engineer54]

You're talking between 5 and 8 Million Ohms! and that is probably not a true reading, you are implying that you are testing with items of current using equipment 'plugged in' and even though you are doing L+N combined to E you will still be measuring any leakages on the equipment.

Surely he's not IR testing with computers and other IT equipment still plugged into the circuits?? I understood him to mean the plugs into the track system supplying the Floor sockets, ...Not with the appliances still plugged into the floor outlets, ...Though i could be wrong..lol!!

 

[IQ Electrical]

Surely he's not IR testing with computers and other IT equipment still plugged into the circuits?? I understood him to mean the plugs into the track system supplying the Floor sockets, ...Not with the appliances still plugged into the floor outlets, ...Though i could be wrong..lol!!

Well if it's only floor sockets, why test L+N combined to earth, a method that should be employed where sensitive equipment cannot be disconnected?

 

[Engineer54]

I did say, ...i could be wrong!! lol!! And as my excuse for oversight, ...it is very late over here!! lol!!

 

[Farmelectrics]

thanks for comments guys all interesting yes iQ you are right pcs are all still connected through various power blocks and i understand im measuring leakage as well I informed client of this and suggested unplugging every device from track just as a sample test to see what readings we would get this would probably take a full days work for 2 guys as there's all sorts plugged in pcs cleaners sockets supply's to underfloor heating boxes you name it oh and this is all with desks tamber units etc above track area nightmare believe me and yes there is a under floor air pressure of 7 pascals constant so i presume this will have an affect on the low readings as well

 

[Engineer54]

yes there is a under floor air pressure of 7 pascals constant so i presume this will have an affect on the low readings as well

It shouldn't , if anything it will help clear any latent humidity in the void...

As IQ suggests 5 to 8 million ohms shouldn't be causeing you any real concern on these underfloor installations....

 

[rocker]

Make them aware of it if you want to... recommend doing it if you want to... if you don't then don't, it's 5 megohms, 5 times better than good enough. In a perfect world it would be infinity, but we ain't in a perfect world.

Personally I would note it and move on, maybe mention it just in case of any comebacks, but I wouldn't be losing any sleep over it.

 

[topquark]

You cannot rely on the results if you have ANY current using in use, particularly computers. It's not wise to even have it plugged in ... as it may be on standby, in which case the power supply may be actively current dumping down the cpc.

 

[Farmelectrics]

thanks for all the replies lads interseting to here your views you never stop learning in this game and a very good site to learn from thanks