Two electricians telling me different things, confused and a bit concerned

[chivers67]

They'll come down in price soon enough Tony but nothing to be concerned about as such.

 

[markyd1]

There is no such regulatory requirement for normal domestic dwellings.

The original version of BS7671:2018 contained a general recommendation that (by implication all) final circuits be protected by AFDDs, but the list of 'examples' of situations in which this might be done included few, if any, applicable to normal domestic dwellings.

In Amd 2 of BS7671:2018, there is again a general recommendation for AFDD protection, but now only for sockets circuits. However there is now also a requirement for AFDDs, again only for sockets circuits, in four specific types of property, namely:

Higher Risk Residential Buildings (defined as residential buildings >18m high and/or >6 storeys, unless over-ridden by local regulations)​

Houses in Multiple Occupation​

Purpose-build student accommodation​

Care homes​

​

... none of which are normal residential properties.

Kind Regards, John

Thanks for the reply John... I already know this but this question was for the guy that made the statement that they do

 

[JohnW2]

Thanks for the reply John... I already know this but this question was for the guy that made the statement that they do

Fair enough - and sorry, but, as you will realise, I took it as a genuine question to which you wanted to know the answer. Maybe an emoticon or suchlike would have helped!

Kind Regards, John

 

[TONY1966]

They'll come down in price soon enough Tony but nothing to be concerned about as such.

Im not worried cheers, glad its done and that nothing tripped when it was done

I know the electrician was saying it is much better to have rcd protection but in all honesty i dont understand what it protects against

The circuit breakers and fuses i think i understand-they protect against overload or short circuit, i see it as the 'deliberate weak spot' to protect the cabling by tripping or melting before the main electrical cable is damaged or a fire started from the generated heat. Kind of the same way mortar is designed to be weaker than brick and crack first.

The RCD however says 'earth leakage faults' but aside from the obvious situation (such as me touching live and neutral wires or cutting my mower line etc) i dont really understand what it will detect.

If a cable is damaged from chemicals or rodents and the insulation fails for example, would that cause an earth leakage? Or if a connection termination came loose?

I dont suppose it matters really with a crawling baby the named benefit of rcd easily justifies the cost.

 

[EFLImpudence]

The RCD however says 'earth leakage faults' but aside from the obvious situation (such as me touching live and neutral wires or cutting my mower line etc) i dont really understand what it will detect.

The main purpose is, as you say, when YOU touch a live wire and YOU are the earth conductor for the current to the ground or also to an earthed appliance.

The other times - like detecting water or slugs in lights etc. - it is little more than a nuisance.

Incidentally the RCD would not detect YOU touching Live and Neutral UNLESS you were also touching something earthed.

If a cable is damaged from chemicals or rodents and the insulation fails for example, would that cause an earth leakage? Or if a connection termination came loose?

Not on its own - unless one of the wires touches something earthed but then other devices also cover that.

RCDs are primarily for the protection of people - your oven doesn't mind the occasional shock.

I dont suppose it matters really with a crawling baby the named benefit of rcd easily justifies the cost.

Better safe than sorry.

 

[Murdochcat]

Not upgrading to a RCBO board would be a daft short sighted decision IMHO

Better safe than sorry

 

[JohnW2]

The RCD however says 'earth leakage faults' but aside from the obvious situation (such as me touching live and neutral wires or cutting my mower line etc) i dont really understand what it will detect.

"touching live and neutral wires" simultaneously will not be detected by an RCD.

The main 'selling point' of RCDs is that will detect the situation when the "earth leakage fault" is through a human being - i.e. when someone simultaneously touches something live and something earthed (not neutral), - but how many deaths or serious injuries this has prevented is far from clear. Having asked many groups of people, many times, over the years, I've so far only come across a couple of cases in which someone has suffered (and survived) an electric shock which caused an RCD to trip, when it is possible (but far from certain) that they would not have survived had there been no RCD.

In practice, the more useful function of RCDs is to trip when there is a 'leakage;' to, say, the metal case of an appliance which, although a hazard, is not a big enough 'leak' to result in an MCB or RCBO tripping (or a fuse blowing) - thereby hopefully disconnecting the supply before anyone has a chance to suffer a shock.

Kind Regards, John

 

[Harry Bloomfield]

Having asked many groups of people, many times, over the years, I've so far only come across a couple of cases in which someone has suffered (and survived) an electric shock which caused an RCD to trip, when it is possible (but far from certain) that they would not have survived had there been no RCD.

I tripped RCD's several times, whilst testing equipment, but the only time and RCD might prove of real use in saving my life, someone had decided it was a good idea to bypass it.

 

[JohnW2]

I tripped RCD's several times, whilst testing equipment, ....

So have I, but only by touching neutral to earth on SP-'isolated' circuits. Are you talking about trips due to currents flowing through your body?

but the only time and RCD might prove of real use in saving my life, someone had decided it was a good idea to bypass it.

.I guess that's a manifestation of You-Know-Who's Law -. although it seems as if your life didn't need 'saving', anyway (unless I'm writing to a ghost !!).

Kind Regards, John

 

[ebee]

I have been known in the past to advocate to customers who were hesitant about RCDs and cost.
"Well if you have a dog and it might save your dogs life you would probably think it worthwhile, more so then for human life surely!"

 

[Harry Bloomfield]

So have I, but only by touching neutral to earth on SP-'isolated' circuits. Are you talking about trips due to currents flowing through your body?

Yep, live testing, where I was anticipating it, and it would not really have bothered me much, hence annoyed by the RCD trip.

.I guess that's a manifestation of You-Know-Who's Law -. although it seems as if your life didn't need 'saving', anyway (unless I'm writing to a ghost !!).

It was a very close one, which I have mentioned before, where I certainly wasn't expecting it, or prepared for it. Understanding the extreme risks of the environment and the need for RCD, I had fitted them. Along came a fool, who thought they knew better, when one repeatedly tripped, decided it was the RCD which was faulty, rather than the equipment.

 

[Notch7]

So you were confused because 2 electricians were telling you different things and now you’ve started thread on here and you’ve got 10 electricians telling you different things

 

[TONY1966]

I have been known in the past to advocate to customers who were hesitant about RCDs and cost.
"Well if you have a dog and it might save your dogs life you would probably think it worthwhile, more so then for human life surely!"

Oh i have no regrets, i can add new circuits now that i have plenty of spare CU slots and to be honest the fuse box was 40 years old, i have no way of knowing if someone had stuck a nail between the contacts or something since i never took the cartridges out.

I will still get the space above the kitchen ceiling checked for polystyrene and i also know british gas left a huge mess in my loft with insulation and their rubbish left everywhere and at least one cable slung across the floor which needs sorting (worst mistake i ever made was getting a boiler from British gas) but as far as i am concerned the CU is one job to tick off . I just need a few months to save for the next jobs now.

 

[TONY1966]

So you were confused because 2 electricians were telling you different things and now you’ve started thread on here and you’ve got 10 electricians telling you different things

Its been really educational

The sad thing is i work for a company that manufactures for the power and electrical industry, but i am so clueless when it comes to electrics.

 

[Murdochcat]

So you were confused because 2 electricians were telling you different things and now you’ve started thread on here and you’ve got 10 electricians telling you different things

Are we telling different things ?