Noise

[luke teague]

what can you do to get a reading when there is noise on a circuit? other than calculate! Zs
what causes this?

 

[MRES]

Unplug items of equipment that could be causeing the noise, ie old PC monitors and PC`s, TV`s etc then try to take your reading.

Tony will know what causes it, I think its something to do with earth leakage. A company I worked for did a bowling alley and there was loads of 'noise' from the monitors above the lanes causeing interferance and a ****ty picture. We ran a clean earth round the circuit back to the main earth bar and it sorted it out.

Fitting filters to the circuit can prevent noise like harmonics.

 

[EasyFox]

UPS's cause noise on some of the circuits at a place where I do regular work.
With the Fluke 1653 I repeat the test a few times & get a result, or as you say calculate it.

 

[luke teague]

might be a silly question but whats UPS?
its strange as i only get noise on the lighting?

 

[EasyFox]

Uninterruptable Power Supply
Loose the mains supply & these babies keep circuits active for x amount of time, the norm on IT kit.

 

[MRES]

Arr the good old UPS. I know of a guy who works for a company that did alot for W H Smith. He completely ****ed a UPS system and all the tills on a brand new store in the Trafford centre at Manchester some years back now !! Company insurance paid out, kid got away with it and the supervisor took all the ****, he wouldnt grass on the kid. Told him to do the right thing and own up but he never did. Supervisor jacked his job shortly after. The kid still works for the said company and still ****S everything up !! Gets away with murder. Followed them on a refit once to find potential 400V at em lights with the ****ing earths cut out !! You know, switch feed off of L1 and em live off of L2. I will PM you the company name if you really wanna know, they are based in Oldham, are NICEIC registered and get away wiv murder !!!

Anyway back to the noise.

 

[tony.towa]

Have you got flourescants or floods (hibay, lowbay, sons, hqi) on the circuit?

 

[luke teague]

na nothing like that loads of 240v downlights could this be the problem, removed all the bulbs and shut everything off but still noise.
i did have it on the sockets when washer and fridge where on! turned them off and it went, but cant understand the lights!
Its a fairly new house on a massive development.

 

[jibspark]

um whats noise?

 

[luke teague]

it comes up on the tester when testing for zs

 

[ccrowe]

na nothing like that loads of 240v downlights could this be the problem, removed all the bulbs and shut everything off but still noise.
i did have it on the sockets when washer and fridge where on! turned them off and it went, but cant understand the lights!
Its a fairly new house on a massive development.

Are you sure they're all LV lamps and not ELVs with transformers hidden in the roofspace? Is there anything running a motor on the circuit. eg fishtank pump.

 

[tony.towa]

Any dimmer switches on the lighting circuit.

Sorry about asking another question, just trying to eliminate "normal potential sources"

 

[luke teague]

on the downstairs lighting there is a 2g dimmer and i got a reading, but nothing on the upstairs. As for the light they are gu10's 230v

 

[tony.towa]

Make sure that the dimmers are at maximum illumination when testing. If you still have noise try bypassing the dimmer with a choc block if no noise you have a dodgey dimmer.

 

[luke teague]

Make sure that the dimmers are at maximum illumination when testing. If you still have noise try bypassing the dimmer with a choc block if no noise you have a dodgey dimmer.

i tried this but still noise on upstairs lighting

 

[tony.towa]

Last logical suggestion, is there an aerial amplifier installed in the loft off the upstairs lighting circuit?

 

[luke teague]

Last logical suggestion, is there an aerial amplifier installed in the loft off the upstairs lighting circuit?

haha, there was one in the loft, near where i was testing for zs a few meters away but was on ring! not lighting