Lack of supplementary bonding - what’s the danger ?

[equitum]

So I know why it is done, where it is done and how it’s done, and when it isn’t required, but I’m yet to see a scenario where there is shock danger in a typical bathroom in a dwelling provided a) the main bonding is in place and b) the CPC’s of all circuits are connected together in the CU (as they will be) and there is no additional protection provided by 30mA RCD .

Consensus is on an EICR code 2 where there is no RCD for additional protection and supplementary bonding is not in place. What is the potential danger ? What am I missing ?

Was my initial punt. We have established that, other than for some very unlikely event, (limited to 0.4 seconds max), none. so an EICR code of 2 is not applicable?

 

[securespark]

(What is a sand boy and who the heck was Larry?)

Pub landlords once spread sand on their floors to catch spills etc... The sand was delivered by lads who were partly paid with ale and thus were merry.

As for Larry, he was Larry Foley, an Aussie boxer, who never lost a fight.
He also played a large part in getting the use of gloves written in to the rules.

 

[Harry Bloomfield]

As I've just written, my personal view is, and always has been, that in the presence of RCD protection, supplementary bonding overs no significant benefit - and the regs now seem to essentially reflect that view.

I support that idea, but RCB's/RCBO's can fail to operate, so call SB a first/second line of defence.

 

[JohnW2]

Was my initial punt. We have established that, other than for some very unlikely event, (limited to 0.4 seconds max), none. so an EICR code of 2 is not applicable?

As we know, probably the most unsatisfactory thing about EICRs is that so much is left to the discretion of the unindividual inspector. If an inspector feels that a hazard which is present only for 0.4 seconds represents 'a potential danger', then he/she is at liberty to code it as C2, even if many others would probably disagree.

 

[JohnW2]

I support that idea, but RCB's/RCBO's can fail to operate, so call SB a first/second line of defence.

As I always say, I will never knock anyone for wanting redundancy of protective devices, but the regs (and most electricians) do not seem to take that view. Indeed, on the contrary, we much more commonly see people criticising the practice of, say, 'putting two RCDs in series' - which is obviously a way of addressing possible device failure.

 

[Harry Bloomfield]

As I always say, I will never knock anyone for wanting redundancy of protective devices, but the regs (and most electricians) do not seem to take that view. Indeed, on the contrary, we much more commonly see people criticising the practice of, say, 'putting two RCDs in series' - which is obviously a way of addressing possible device failure.

Which has reminded me - I now have two RCD's in series, feeding my garage.

 

[JohnW2]

Which has reminded me - I now have two RCD's in series, feeding my garage.

I have the similar,and would not knock either of us for that (although some people would)

 

[equitum]

Probably a Type A downstream of an AC

 

[ebee]

In the 15th Ed., yes!!

As for RCDs, there is a great reliance on them, to do their job, especially in this context of supplementary bonding, touch voltages, etc, but these things do fail regularly.

I'm in the bond & RCD camp.

Hah. A kindred spirit.

 

[ebee]

Pub landlords once spread sand on their floors to catch spills etc... The sand was delivered by lads who were partly paid with ale and thus were merry.

As for Larry, he was Larry Foley, an Aussie boxer, who never lost a fight.
He also played a large part in getting the use of gloves written in to the rules.

So my daft saying of being as happy as sand boy called Larry is not as totally bonkers as i meant it to be? Gosh if it gets any worse I might be in danger of speaking truths in my little witicysms! I will have to try and avoid that.

Sorry for not contributing I,m on a foreign holiday.
Not not Yorkshire or Cumbria,
Peaks

 

[ebee]

I think the 50v or less is for normal dry conditions, special locations need a bit more protection.
Has anyone ever been touching a 50v bog standard phone line whilst ringing signal is active? It does bite even in normal dry conditions!

Not that long ago really, lighting circuits had a permissible 5 seconds earth fault clearing time (ok it was still supposed to be 0.4 seconds for bathrooms ) but even 0.4 seconds can be too long for comfort.

I became a fan of supp bonding and remained so even when RCDs were mandated on most circuits. Even the speed of working RCDs could still leave one uncomfortable. Then factor in the possible failure rate of RCDs (not just complete failure to actually disconnect at all but the failure to do so within the required time.

And even then I would not deliberately forgo the caution of avoiding touch. It does surprise me (or rather it does not) that some folk take the view , testing or working on, a live circuit , " oh its only 5 amps" or " its only 50v!" I would still avoid it..

Putting aside the age old game of "catch this capacitor" I have only had a mains shock once at about 12 years old and a BT line zap once in adult life.
Both incidents taught me to avoid such stings.

 

[Harry Bloomfield]

Probably a Type A downstream of an AC

You do like to second guess.

 

[Harry Bloomfield]

Has anyone ever been touching a 50v bog standard phone line whilst ringing signal is active? It does bite even in normal dry conditions!

It's due to the inductance, the 50v is much more than 50v, and yes, I suffered them many times, working in GPO exchanges.

And even then I would not deliberately forgo the caution of avoiding touch. It does surprise me (or rather it does not) that some folk take the view , testing or working on, a live circuit , " oh its only 5 amps" or " its only 50v!" I would still avoid it..

I spent much of my working life, working live, often it is the only way to test and diagnose. It was never the live working which bothered me, so much as the working on equipment which was supposedly dead, and that catches out unexpectedly.

 

[securespark]

Has anyone ever been touching a 50v bog standard phone line whilst ringing signal is active? It does bite even in normal dry conditions!

Hell, yeah!

 

[JohnW2]

Probably a Type A downstream of an AC

I can#t speak for Harry, but mine are both Type ACs