Protek RCDS

[No1]

Anyone had any problems with Protek RCDs?

I got called out to a job last week, TT supply, Protek RCD consumer unit and RCD had tripped and would not reset, did the usual tests and everything Ok but still would not reset.

I removed the RCD and drove home with it to see if I had one in my garage, I didn't, so had a ring round and no-one had them in stock.I went back to the job and refitted the RCD and tried it one more time, and this time it stayed on.

I tried the test button and it tripped, reset it no problem, checked it with RCD tester and everything fine.Plugged everything back in and turned appliances etc on, no trip.

Any ideas on this?, I put it down to either dust/grit inside RCD or I had released something inside with the vibration of removing it.

Then today I have wired a supply to a metal portacabin, TN-C-S supply at origin and I have TT'd the portacabin Ze of 0.26 ohm.Again a protek RCD consumer unit, RCD not tripping at all on X1 but tripping on X5 in 18.9 ms and 8.9ms, did a ramp test and tripping at 33mA.

 

[Andy™]

when you TT'd the portacabin, did you isolate the TNCS earth connection from the rod & cabin earth?

and what are the 'usual' tests you carried out, and the readings you got?

 

[No1]

Hi Andy

Yes I did isolate the TN-C-S earth, I used the steel support of the loading bay as my earth electrode.

Unplugging all appliances and doing insulation resistance tests.

 

[Andy™]

is this steel support you used bonded to the TNCS earth? and i assume the 0.26 you got was the earth electrode in isolation?

 

[No1]

Hmmm, now there's a thought, I bet it is.I thought the reading was good for TT.

It looks like I will have to put an earth rod in afterall.I have tried to avoid it as the portacabin is sited on a concrete base that doesn't belong to the people i'm doing the work for.

 

[Andy™]

any soil or anything nearby? if you know whats under (or more importantly, that something isnt under) the concrete base you could drill a hole slightly larger than an earth rod and hammer one through it. you may need a 2 metre rod for a decent reading though

 

[No1]

No, there is no soil nearby.It looks like I will have to do as you say and drill through the concrete next to the cabin.

 

[Andy™]

No, there is no soil nearby.It looks like I will have to do as you say and drill through the concrete next to the cabin.

looks like it

 

[Lurch]

Anyone had any problems with Protek RCDs?

Yep, fitted a 3 phase board with 100mA TD incomer and a few 30mA RCBO's. The incomer now thinks it's a main switch. See if I can get something else to fit I think.

 

[No1]

Andy, thanks for that.

This is one of those jobs I didn't want to do in the first place, but it is for a friend so I couldn't really say no, but I didn't really have the time to do it.