However HW is connected to CW by the mixer taps (all copper pipework). Boiler primary loop is connected to HW via hot water cylinder. CH loop is connected to boiler primary.
Irrelevant unless in a bath/shower room etc.
Towel rail and rads via CH loop.
Presumably they are in the bathroom so can (if not isolated) be bonded to other extraneous parts and the CPCs of all the circuits of the location.
It *is* connected electrically and *is* in a bathroom. It *may* meet impedance requirements through it's own connections, especially as all is RCDed and provided that they work the disconnect times will be short enough to protect, but as I've not go the kit and the delta cost to bond is about a tenner versus 180 notes for LABC to visit twice I'd like to hedge that bet.
I suppose that should have started with 'If', then yes.
This is ok by the rules, albeit wasteful in materials, right?
Yes, but only in the 'special locations'.
It is not needed elsewhere, e.g. kitchen.
We got there in the end!
Yes, my bathroom has hot/cold taps and heating, and all plumbing is copper and is connected electrically.
No, supplementary bonding probably isn't needed. The CH/HW don't connect to planet earth (run through the floor-ceiling void, not buried in the concrete slab, and I flippin' well hope my walls aren't that damp/salty), and if you've got an RCD you're not worried about something inside the house shorting against them and causing them to become live. Even without the RCD, the pipework itself ought to pass any Z testing, but it isn't expensive, contrary to regs, or making the installation more dangerous to supplementary bond and be done with.
I appreciate that I've an awful lot more visibility of the plumbing here though! Thanks for the patience.
A very different story if the taps and CH are isolated by virtue of plastic pipework. Here supplementary bonding would make it more likely that these were live.
ban-all-sheds: You'd be an awful lot less cryptic and an awful lot more helpful by referencing this particular installation rather than all in general. The lines of reasoning presented were an attempt to justify *not* improving an existing bond between the HW/CH and the CW, rather than a description of the purpose of earthing/bonding.
If you wish to apply supplementary bonding as if RCDs were not installed then that is up to you.
With 100A TN-S supply - 10mm² Earthing conductor and 6mm² Main Bonding is adequate but I appreciate that you may get an inspector who doesn't know how to work it out and only reads the dreaded 'guides'
"No questions your honour; belt and braces, belt and braces..." is the response from LABC I'm after. No paper to your name means no discussion regardless of how right they may be to insist on, say, 16 mm^2 bonding or unnecessary supplementary bonding that in this instance is harmless.
Phonecall #1 told me to naff off and have the electrician fit an earth rod/make it a TT system as "it wasn't their job."
It is their responsibility to maintain the earth connection. You should not tamper with the incoming cable.
They have the photos, and will advise whether this is the MET terminal that they are providing on a TN-S or TN-C-S system (and something that they're taking responsibility for, pipe clamp and all) or whether it is meant to be a TT system that somebody prior to myself has kludged.
Phonecall #1 didn't want to know. Not our job to provide an earth, naff off and bang in an earth rod. #2 asking about bonding the big lead thing entering the property, or whether it was supposed to be an earth, resulted in the photos being asked for.
Presumably these (presumed dead; being confirmed tomorrow) gas pipes don't need bonding if merely pipes not in a bathroom, but do need bonding if still live?
, on Flickr
I've lifted yet more floorboards to clear the run to the gas supply and with regards the "other" query tacked onto the original post:
-The house had an attic conversion with 4 double sockets daisy-chained (radial, or spur off a spur off a spur, how would you describe?) and hooked into the upstairs lighting circuit. Can I add a 13A fused faceplate to the ring main and hang the lot off the output of that? It'll be quick/dirty/good enough for a hairdryer.
-Is a shed fed in 2.5mm^2 by a 13A fused faceplate on the ring acceptable?
Now propose two 16A MCBs and wiring back to the board as a single 2.5mm^2 each instead of the FCUs.