oh dear (Crafty's shed update)

[Steve]

My Hager RCD in my shed doesn't work!!!

Heres the breakdown:

SWA straight into house CU, no gland (but still properly glanded at shed)

The guy must have looked in the shed CU to see which core does what in the SWA, but failed to notice that there's an RCD at the shed, and wire accordingly at the house!

(UNLESS he tested the shed RCD and then wired it to the RCD in the house because it doesn't work. Doubt this though.)

Identified the grey earth core with bits of G/Y sleeve taped to it with brown tape Neutral left plain black.

And the ballasts in those B&Q fluorescent lights are very noisy!

What are TLC like for returns / replacements? The RCD came with the CU, will they be able to just swap the RCD?

 

[JohnD]

Faulty device out of the box is less common than a mistake in installation (sorry!)

Go through the RCD fault-find flowchart. If it really won't work in the shed, you could carry it back to the house and build a little test rig.

 

[RF Lighting]

Has he actually connected the shed supply up properly? If it is not then this may explain the RCD not working. What is wrong with it? Is it the test button that doesn't work or was it tested properly with an RCD tester.

 

[the_jinj]

So to clarify - you have the RCD in the shed CU connected to the RCD in the main CU?

 

[Steve]

test button croaked it. just pushes in, doesnt trip. Earth, neutral and phase all connected correct both ends.

Could having 2 identical RCDs in a line like this affect the test button?

 

[Spark123]

No, however if the house RCD is tripped the shed RCD will not trip as it has no power.

 

[Steve]

No, however if the house RCD is tripped the shed RCD will not trip as it has no power.

power was all up and running - had a couple of appliances running in the shed for good measure, to make sure current was flowing when i pressed test.

 

[JohnD]

can't see how. The test button just creates a slight current which unbalances it. You have got a healthy supply when you press the button, lights working in the shed and so on?

I've usually only seen test buttons fail with age, and had assumed it would be tarnish on the contacts. Did once have one DOA, all the others in the box were OK, sent it back, makers checked the datestamp, tested it and sent me a new one That one I'd tested myself with a 400mA fault current and it still wouldn't trip, so it wasn't the button.

 

[Spark123]

When you manually turn the RCD off does it isolate the sockets/lights? It is sounding more like the RCD is at fault, can you confirm the supply wires both go into the top of the RCD?

 

[Steve]

Yes, i wired it so i know i did it right live and neutral both go into the top, live busbar and neutral bar connect to the bottom. And yes, the switch does isolate the board when it is flicked down. Dont know if this is any indication of it working, but when it is pushed "on" it "clicks" 3 times on its way up, quite hard to push. Main man is coming wednesday to issue a certificate AFAIK, so he will probably test everything then.

 

[Spark123]

I've usually only seen test buttons fail with age, and had assumed it would be tarnish on the contacts.

I've seen one go up in smoke when muggins got the supply/load terminals mixed up.

 

[Spark123]

Yes, i wired it so i know i did it right live and neutral both go into the top, live busbar and neutral bar connect to the bottom. And yes, the switch does isolate the board when it is flicked down. Dont know if this is any indication of it working, but when it is pushed "on" it "clicks" 3 times on its way up, quite hard to push. Main man is coming wednesday to issue a certificate AFAIK, so he will probably test everything then.

It sounds like the RCD is faulty to me, hopefully TLC will either send you a new RCD or a new CU, where you can swop the RCD over and return the faulty one in the CU. Your man on Wednesday should be able to tell you for definate wether or not the RCD is faulty.

 

[securespark]

If you have access to a tester that can auto test the unit. try that. But at the end of the day, the test button should trip, and if it doesn't it is goosed. Have you got another you can temporarily put in its place to see if it works?

 

[jondiy]

If you don't have a tester, Why not flick your sockets mcb off at the shed end (leaving the rcd on) , remove a shed socket, and short a neutral to the earth, see if you can get the rcd to trip out.

This will at least verify the actual mechanical operation of the device. Only trouble is , the house rcd may trip first - but it could be worth a try.

 

[JohnD]

fair move, though if the test button doesn't work the the RCD needs replacing, as securespark says.

You can also make up a test rig with a bulbholder wired earth and phase, a 25Watt bulb is very roughly 100mA (more at cold start-up)

It is very important to dismantle the rig immediately after use.