CORGI visit - queries on regs

[ARWadsworth]

Yep. What the odds?

Adam

[fred]

In article , Mike writes

What you are describing is an incidental connection, it doesn't count for safety. In a fault condition, a bad connection to a pipe may be enough to case a fatal shock but not good enough to trip a protective device.

[Mike]

How can it ? For the electrons to even get to the pipe, they have to pass through the boiler fittings which ARE earthed properly.

[Coherers]

413-02-02: "In each installation, main equipotential bonding conductors (see table) complying with Section 547 shall connect to the main earthing terminal for that installation's extraneous-conductive-parts including the following: water service and gas installation pipes; other service pipes and ducting; central heating and air conditioning systems; exposed metallic structural parts of the building; the lightning protective system'.

What odds would you like?

[fred]

In article , Mike writes

Are they?

[Mike]

Yes - that IS in the regs. Can somebody actually point to an IEE paragraph that requires bonding the pipes. I certainly don't have this in my installation and cannot see a need for it.

[Mike]

I think you are taking this too literally. The meaning you are proposing it has would require every separate piece of central heating pipe to need it's own bonding wire as you are saying the compression joint doesn't provide guaranteed earth continuity. This is obviously a nonsense. And if the joints around the system have guaranteed conductivity then so do those at the boiler.

Indeed implemented this strictly, every RSJ would need an earthing terminal which would be insane.

Also this paragraph is out of date - lightning protective systems do not now go to main earth - this destroys modems and the like - they must have their own separate ground connection.

[Dave Plowman (News)]

I've yet to see anyone earth bond cast iron guttering. Will this fail an inspection? Oh - and Crittall windows?

[ARWadsworth]

What have you got? I'll take the lot apart from the wife and kids.

Unless the CH is for some reason an extraneous-condutive part I will take any odds.

Adam

[Coherers]

Ah. My original text is a bit ambiguous. Sorry.

The bonding needs to be *between* the CH pipes and the origin of the installation (i.e. CU etc.).

The regs don't specify where the bonding should be attached to the CH pipework (unlike the gas service), but flow & return near the boiler seems as good a place as anywhere. And under the floorboards is best aesthetically.

[Coherers]

I don't really buy the compression fitting stops continuity argument. If they interpreted it like that, supplementary bonding would be mad too. For stuff like this, you don't need a 100% guarantee of continuity, just something to improve the odds. All I think you need to do is put a couple of straps on and take it back to the earth block. Just like with the gas. No more, no less. Really not onerous. Honest.

Only if exposed.

Actually, there was a recent case where a workman was killed because there was live buried metal work and the wiring committee were discussing if this had implications for future changes - it only applies currently to exposed metalwork. Briefly discussed in here:

this bit on the right of page 1: "The previous guidance of the joint committee has been that steel framework would generally require neither earthing nor main bonding provided insulated and sheathed cables were used ...." I don't think they will change it though, 'cos as you say it would be mad.

Interesting, don't know anything about them. But I would have thought "lightning protective systems" would be outside the building anyway, so would not need to be covered anyway. Odd.

[Coherers]

It is. Almost all metal pipework will be. If it might be connected to earth somehow.

Extraneous conductive part: "Metalwork that is not part of the electrical installation, and which is liable to introduce a potential, generally earth potential" ( c.f. Exposed conductive part. )

Here, have a look at this thread on the IEE forum discussing whether a suspended ceiling (!) is such a part:

(Verdict, No - fortunately). But it goes to show what we are dealing with.

Are you really sure you want to go "All in" on this one ??? I've got a big stack of chips here..... ;-)

[Lurch]

On Fri, 10 Dec 2004 22:41:47 GMT, "Coherers" strung together this:

I'll take any odds. Do you actually understand the regulation?

[Lurch]

On Fri, 10 Dec 2004 23:09:27 GMT, "Coherers" strung together this:

Read up on equipotential and supplementary earth bonding, then come back.

[Stephen Dawson]

Have a look at th reg fully, and look at 547 as well. You do not need to cross bond a boiler.

[Coherers]

I have absolutely no need to, and in the absence of you putting forward evidence to the contrary, I would suggest that perhaps it is someone a bit closer to home in need of some technical training.

As you don't seem to be interested in the regulations, perhaps you would be interested to read what Marks says in the "Handbook on IEE Wiring Regulations BS7671"

Main Equipotential Bonding

Extraneous conductive parts that extend throughout the installation shall be connected to the main earth terminal at the origin of an installation by main equipotential bonding conductors, including the following items:

1. Main water pipes.
2. Gas installation pipes.
3. Main service pipes and ducting.
4. Central heating and air conditioning systems.
5. Exposed metal parts of the building structure.
6. The lightning conductor system.
7. Metallic sheath of telecommunications cable ( subject to the owner's or operators consent).
8. Extraneous conductive part which is in direct contact with earth. 413-02-02 and the Electricity Supply Regulations.

[Dave Plowman (News)]

I can't see any copper to whatever connection - if fully tightened - not giving a decent earth path.

[Coherers]

Great. The words "candy" and "baby" come to mind.....

Yes, perfectly.

Take a look at this on the IEE site. The publishers of the f***ing regs for gods sake!

the title)

From the right of page one:

In each electrical installation, main equipotential bonding conductors (earthing wires) are required to connect to the main earthing terminal for the installation the following : . metal water service pipes . metal gas installation pipes . other metal service pipes and ducting . metal central heating and air conditioning systems . exposed metal structural parts of the building . lightning protection systems

Another IEE thread

the third post:

Central Heating: Yes, the central heating pipes should be directly bonded back to the main earth terminal as part of the main equipotential bonding (i.e in 10mm2) (regulation 413-02-02). (Not necessarily from the boiler, but that's probably a good a point as any)

JEEZ what I have gotto do here ?? It is really simple...

Where is Andy H and Christian M?

Help guys!!

[Coherers]

Outside, so hopefully you would be okay. I think the equipotential zones are only required inside the building

Now that is an interesting thought. I read something somewhere about the danger of cross-bonding metalwork that was exposed to both the inside and the outside because, although it is safer for those inside the zone, it can create a hazard to people outside of it.

[Coherers]

Totally agree, you don't have to bond the boiler. Just the CH pipework.