A few bonding questions...

[slippyr4]

Supplementary bonding in my bathroom.

There are no electrical services other than lighting. The bath is plastic, the pipework is copper. No metal building fabric.

1) My understanding is that I need to bond hot water pipe, cold water pipe, and CPC of the lighting circuit, and nothing else. Does that sound correct?

2) I have central heating pipes running under the floor, but they are not exposed in the room itself, nor do they contact the HW or CW pipes in the bathroom. They are bonded elsewhere. I therefore think that these should not be included in the supplementary bonding. Correct?

EDIT- Duh, Since i'm having a towel rail (when i get round to fitting it), then my flow and return will need bonding.

3) If I run the bonding conductor inside a studwork wall (for the run between lighting CPC and the pipes), Since the wall is less than 100mm (ie, 2 x 50mm) thick, then does the bonding conductor need additional protection? I'm a little unclear on this- if it was a live conductor it'd need earthed metal protection, but this conductor *is* an earth.


4) Is there any requirement for bonding straps / points of connection to be accessable, or even visible? or can they remain under the floorboards. Obviously I'm aware the the LABC monkey may want to see them, but I can lift floorboards for that.


Thanks for the info.

PS, i know all about part P, i'm doing a legal rewire.

 

[slippyr4]

Can anyone help?

 

[dingbat]

There are no electrical services other than lighting. The bath is plastic, the pipework is copper. No metal building fabric.

1) My understanding is that I need to bond hot water pipe, cold water pipe, and CPC of the lighting circuit, and nothing else. Does that sound correct?

You must bond together all 'extraneous conductive parts' with the ciruit protective conductors of any circuits in the bathroom zones. Basically, anything you can touch which might possible introduce a potential (including earth potential) into the zones. So, yes, it sounds like you've got it, but check that your waste pipes are not also conductive.

2) I have central heating pipes running under the floor, but they are not exposed in the room itself...

Can you touch them? No? No point in bonding.

3) If I run the bonding conductor inside a studwork wall... does the bonding conductor need additional protection?

No, but ideally you should run it within a prescribed zone, e.g. within 150mm of an internal corner.

4) Is there any requirement for bonding straps / points of connection to be accessable, or even visible? or can they remain under the floorboards.

All screwed connections must be accessible for inspection, testing and maintenance (Reg: 526-04-01) Under the floor is not accessible, especially as it is entirely likely that somebody will tile over that floor in the future .

 

[ban-all-sheds]

//www.diynot.com/forums/search.php

 

[slippyr4]

Thanks dingbat.

I can't find any definition or guidance on "accessible" in the regs. Is there one? or is it open to interpretation?

Would behind a bath side panel which is removable with a tool count as accessible?

Failing that, I guess I could solder the bonding conductor as per 526-04-01 (iii).

 

[ban-all-sheds]

The thing that ha always intrigued me is this.

If you use soldering/brazing/crimping to make a connection that doesn't need to be accessible, and then make it inaccessible, how does anybody in the future confirm that it is the type of joint that doesn't need to be accessible for inspection?

 

[slippyr4]

agreed. i also can't see why a properly made screw connection is regarded as more likely to fail than a crimped one. They are both "compression", although not to the regs version of compression.

eg, if i crimped a loop terminal onto the end of the bonding conductor, screwed the loop to the earth clamp, using a shakeproof washer, it ain't coming undone on it's own.

The only counter-argument that i can see is that a screwed connection is not secure if it's not properly made in the first place, but that applies equally to soldered connections, crimps etc.

It just seem a bit silly.

 

[TraineeSpark]

Sorry to (slightly) hijack post. But its on the question of the bonding conductor in a stud wall. Although many times I have seen (/done it myself) a bonding conductor run through stud wall/ chased and plastered into masonry/ run down a wall in pvc trunking etc. never been 100% sure how acceptable this is. Am aware how ambiguous the Regs are on this, but providing there is no other route (i.e adjacent airing cupboard) and cable is run in permitted routes etc. can anyone see anything actually wrong with it?
Has anyone come up with a better option, cause i sure as hell cant think of one?
TIA Guys, TS.

 

[TraineeSpark]

Obviously not then guys.