Fault finding query

[dav1980]

Any thoughts on this would be a great help.

I've got a 4pole 300mA rcd feeding a DB section through a contactor. The section in question feeds a load of 250/400w hit fittings through SP mcbs (4 per mcb x5 ). There are some other circuits on there but I've ruled them out.

The problem being that the front rcd trips when the lights are switched through the controller/cell. I've removed the controller from the equation, tried bringing them all on 1 circuit at a time. This only works when I do it slowly. I was thinking its to do with all the control gear coming on at once

Ramp tested the rcd 210mA. This seems low to me so I'm going to change it over but is it normal to have such a high fault current from these fittings? Or maybe the contactor could be giving me some problems also?

cheers

 

[dav1980]

Got a mewp hire next week so I'll see what's up there then. Lights are on 24/7 for the moment . Thankfully this site will be gone shortly , nothing but hassle from it.

 

[Leesparkykent]

Thanks guys, I was wondering what the leakage on the fittings would normally be. So if 2mA x 20 fittings = only 40mA so is well under the 210mA my rcd is tripping at on the ramp test.

So so probably a combination of old control gear and possible contactor issue. What about my rcd? I thought I should be changing it as its tripping well under 300mA?

Was the load disconnected when ramp testing the RCD?

 

[dav1980]

Was the load disconnected when ramp testing the RCD?

Yes mate.

 

[Leesparkykent]

Yes mate.

The BS requirements for RCDs states that the RCD should operate between 50% and 100% of its rated tripping current.

 

[dav1980]

The BS requirements for RCDs states that the RCD should operate between 50% and 100% of its rated tripping current.

So mines is tripping at around 70%. Might change it over anyway and hope for the best.

 

[infinity]

Swap them out for LED, get a better light and save money at he same time! Everyone's a winner then!

 

[amlu]

get a leakage tester and have a look, find out whats leaking. easy to do on a radial. maybe connections on some lamps are covered in dirt or damp somewhere.

 

[dav1980]

Swap them out for LED, get a better light and save money at he same time! Everyone's a winner then!

Most of our sites have / are getting led upgrades, this particular site is being punted off our contract so im just looking to tide them over for the moment.

I do agree the led lighting now is more cost effective in the long run, and a nicer brighter light.

 

[dav1980]

get a leakage tester and have a look, find out whats leaking. easy to do on a radial. maybe connections on some lamps are covered in dirt or damp somewhere.

Good shout, like I say will be getting up there next week for a closer look. Think I will ask for a leakage clamp meter now I can justify it lol