Microbore Earth Bonding

[Charles Middleton]

Hi,

Just fitted a towel radiator onto my Microbore CH system (thanks for all the advice received). The only thing left to do is to attach the earth bonding which was previously attached to the now replaced standard radiator. On the old radiator there was a small clip and the earth bonding has (not sure on name of fitting!) like a spade connector but fully closed. This was just screwed onto the clip.

There is no clip on the towel radiator so I need some sort of fitting to clamp around the 8mm pipe that I can then screw this connected onto. I've have a look at some jubilee clips and the smallest I can get is around 10mm and in any case I would need to remove the connector and just clamp the splayed wire to the pipe with this method.

What I need is some sort of connector that will clamp the pipe, screw tight, and in which I can put the screw through the connector and tighten the lot together.

Hope that makes sense and any help gratefully appreciated.

CM.

[Charlie]

How about making a collar to increase the diameter? A ring of conductive pipe, with a cut through it so you can slip it over the microbore.

Charlie

[Dave Plowman]

I'd have thought if you need earth bonding on a system which has copper pipes, the bonding should go on the rad - not the pipes. If the TRVs etc have any form of gunge between them the pipes and the rad, this could introduce electrical resistance.

[Andy Hall]

The ordinary earth clamps work fine for this.

e.g. Screwfix order no. 18129.

You have to have the "Safety Electrical Earth Do not Remove" label anyway,.

.andy

To email, substitute .nospam with .gl

[Charles Middleton]

Sounds like a good idea!

CM.

[Grunff]

Hmm, interesting thought. All of the bonded setups I've looked at (in my capacity as a nosy visitor in other people's houses) have had the clamps on the pipes near the radiator, not on the radiator itself. I've often wondered about the electrical usefulness of this.

[Lurch]

On Fri, 30 Apr 2004 13:16:04 +0000 (UTC), in uk.d-i-y "Charles Middleton" strung together this:

Erm, an aptly named earth clamp is what you want, a few pence from the local electrical wholesaler or infinitely more from B&Q etc..

[Martin Angove]

Well, until the likes of Screwfix D18129, you would have had to drill through a bit of radiator and fit a nut, bolt and a couple of shakeproof washers (for better contact) in order to bond the rad. itself. Bonding both pipes just south of the valves using easily available pipe clamps probably seemed like a good second best.

Try D18129 though - it does the job just fine.

Hwyl!

M.

[G&M]

Or simply don't bother. There has been a lot of discussion on this in the IEE and general consensus is it isn't needed in dry rooms.

[Christian McArdle]

However, strangely, such a result would actually be safer (particularly if both pipes are reliably bonded). The worst case scenario here is that (unless there is another source of earthing different from the pipe connections) the earth potential will be the same as the supplementary equipotential zone, but with increased resistance, perhaps reducing maximum earth fault current to below a fatal level. The best case is when there is total isolation between the pipes and the radiator, when supplementary bonding isn't required.

Christian.

[Martin Angove]

Ummm... depends what you mean by a dry room. Personally I'd not bother to bond anything anywhere except in the bathroom: not even in the kitchen or "cloakroom", but AIUI bonding in the bathroom (section

60-something, "locations containing a bath or shower") is strictly required within the zones, and very few bathrooms have the kinds of dimensions which mean that such items are outside the zones.

Hwyl!

M.

[G&M]

Agreed, bathrooms definitely need earth bonding. If you are using a towel rail this is easiest as you can often do it on the mounts.

For kitchen it depends where the radiator is. If you can't touch it and the sink I'd regard it as dry.

I'd probably bond in the cloakroom if I had a radiator there.

[Martin Angove]

Why though? The only reason to be worried would, I think, be if you are concerned that there will be >50V (that's what bonding is supposed to prevent) between one of the taps and the radiator for enough time to cause you problems. If the rest of your system is up to scratch (main EP bonding, earthing, circuit protection devices) then this is unlikely to be the case I'd think.

Supplementary bonding is more important (and therefore mandatory) in bathrooms, showers, swimming pools etc. because your body tends to have a much lower resistance in a bathroom than it normally does elsewhere - no shoes, wet skin and so on. This can lead to much higher currents which are (to put it bluntly) more lethal in a shorter time.

Well, that's the way I look at it anyway.

Hwyl!

M.

[G&M]

Our earth (actually the neutral in from an aerial line) is about 70 volts away from the ground outside. Plastic piping and drainage in theory stops the taps and radiators being at outside ground but prefer to enforce the issue.

Would like to connect my earth to ground outside but there are four farms downstream of me and my earthing spike would have to be capable of handling their fault conditions which in our well drained soil may not be possible.

[usenet]

Why not go for a TT system then?

Or maybe you can report the 70 volt difference as a fault to the electricity supplier.

[G&M]

TT system

Not spec'ed. Where we are if it's on that's an achievement. We are so close to 253volts it's untrue so that the farm at the end has enough voltage to at least turn his lights on.

[usenet]

Do you mean you already have a TT system? In that case you have a fault as you should be using your own earth, not the supply one.