electric boxes on stud walls question?

[Sidewinder]

I'd had my fair share of shocks, but from my IT side of things, I've grown to hate the damn things! RCD trips in the middle of the night, next you know is an half hour later when the UPS fails!

Well in that case there is a fault that needs identifying and fixing.
If you have had shocks then you are a dangerous person to be working around as you are regularly breaking the Electricity at Work Regulations and are putting other people in danger, and you could easily kill someone else because of your actions.
The posts you have made that I have replied to show in no uncertain terms that you have a very poor understanding of fixed electrical systems and how they should be installed, maintained, modified and utilised.
You are very lucky to be alive if you have had mains supply shocks, and, if you think about it, it could well be an RCD that has saved your life.

As has been already said, electricity is almost as much of a silent killer as CO.

 

[Cyberprog]

Well in that case there is a fault that needs identifying and fixing.
If you have had shocks then you are a dangerous person to be working around as you are regularly breaking the Electricity at Work Regulations and are putting other people in danger, and you could easily kill someone else because of your actions.
The posts you have made that I have replied to show in no uncertain terms that you have a very poor understanding of fixed electrical systems and how they should be installed, maintained, modified and utilised.
You are very lucky to be alive if you have had mains supply shocks, and, if you think about it, it could well be an RCD that has saved your life.

As has been already said, electricity is almost as much of a silent killer as CO.

Faults, such as Power Supplies dying, can cause RCD's to trip. I know what I'm doing, and I fail to see how I'm a dangerous person to be working around! I have a very good understanding of fixed electrical systems, but as I've said, in my background RCD's are not the most suitable thing to be using. If you have RCD's in a datacentre environment you could easily have one piece of equipment fail and take a large amount of servers off-line, potentially causing thousands, to hundreds of thousands of pounds of damage and lost revenue. So it depends upon your background, and the installation environment as to what protection is in place. I've seen people nearly lose fingers to DC bus-bar systems thanks to jewellery as well!

You can now get automatic re-closers for RCD's, but these only work with certain brands IIRC. I expressed my personal preference for this, they've caused me more problems than they've saved.

 

[BrokenBiker]

ah, but your original comment was based on rcds in a workshop, not a data centre.

regardless of where you are working and what you are doing the electricity at work regulations state you much check all equipment for dead before proceding to perform work on them, eliminating any risk of serious shock.

if it weren't for rcds even a small mains shock can kill you easilly, and its this misunderstanding that you think rcds are there to cause problems and not protect people is what could potentially make you a dangerous person to work around

 

[rtbcomp]

Faults, such as Power Supplies dying, can cause RCD's to trip.

But there must be a leak to earth for them to do this. If there is a faulty earth on the building then the frames of other computers can become live. I've seen this for myself after I networked 2 machines for a customer - there was an earth fault in a junction box and the network cards blew. An RCD would have prevented this.

Furthermore a faulty power supply needs to be switched off before it causes more damage to the computer, an RCD does this quickly and automatically.

 

[Robotstar5]

ah, but your original comment was based on rcds in a workshop, not a data centre.

I would imagine data centres come under their own section of the regs (543.7) with earth monitoring, high integrity earth etc. so does not apply to workshop wiring.

 

[owas]

Mine will be definitely br rcd protected, ive never had an electric shock in my life and dont plan to anytime soon

Small workshop

 

[Sidewinder]

I'd had my fair share of shocks...

Cyberprog,
This comment of yours is why I felt that you were a danger to yourself and others.
In this day and age you simply should not be in a position to be getting an electric shock, if, you are working safely and in accordance with statute law and accepted industry practice.

 

[Sidewinder]

... If you have RCD's in a datacentre environment you could easily have one piece of equipment fail and take a large amount of servers off-line, potentially causing thousands, to hundreds of thousands of pounds of damage and lost revenue...

If you have RCD's in a data centre and they are protecting more than one item of equipment, or at the most one circuit that supplies IT equipment, then the design of the system is not correct, as I said in my earlier post:

When the are correctly specified, correctly installed and correctly utilised, they are life saving devices.

The specification part is down to the circuit designer, now yes I would find it unusual to have them in a data centre, and as has already been suggested reg group 543.7 will apply.
The equipment in use means that RCD's are pretty much excluded on supplies to IT equipment.

However, that does not mean that they should not protect general use sockets in a data centre environment, they should.
However, there should be suitable and sufficient design thought and the design risk assessments for the supplies should have identified the potential issues and these should have been designed out before the first wiring was ever installed, as to whether there was to be, or not to be RCD's used, and on what circuits.

Anyway, we were not however discussing data centre applications, as you would also require high integrity protective conductors, as per the reg group above there also.

We are talking about metal working workshops, there an RCD is definitely in the camp of being a potential life saver, with the caveat I put in to my earlier post repeated above.

Although they are not necessarily compulsory, and will still not be compulsory under Amd3 when it comes in, though the RA done in conjunction with the client would need to be sufficiently robust and well documented to prove this.

For ordinary persons not under EAWR, you would have a very difficult job justifying leaving them off a general use socket outlet, including a 16A BS EN 60309-2 type.
Even for locations covered by EAWR, it is going to be difficult to justify leaving RCD's off normal socket outlets shortly without a robust RA undertaken with the duty holder.

 

[Cyberprog]

Cyberprog,
This comment of yours is why I felt that you were a danger to yourself and others.
In this day and age you simply should not be in a position to be getting an electric shock, if, you are working safely and in accordance with statute law and accepted industry practice.

Usually down to crappy equipment on this one, hire companies can be very poor for safety when it comes to the events side of things... Why is me getting a shock making me a dangerous person? I'm just like ******* flypaper to them, if anyone's gonna get a belt, it's always me!

 

[Sidewinder]

Usually down to crappy equipment on this one, hire companies can be very poor for safety when it comes to the events side of things... Why is me getting a shock making me a dangerous person? I'm just like ******* flypaper to them, if anyone's gonna get a belt, it's always me!

OK, I'll forgive you, partly, however, why should you have to put up with the hire companies providing kit that could well kill someone.
The answer is you should not.
IF you have had shocks off hire kit then it is not fit for purpose and the hire company are breaking several laws and obtaining money by deception, that is fraudulent, or you are "playing" with things you should not be in ways you should not be.
Either way laws are being broken and peoples lives are at risk, why, in this day and age, when these things are so easy to avoid is such a situation seen as acceptable.


BTW, sorry for the digression from the original thread.

 

[Cyberprog]

OK, I'll forgive you, partly, however, why should you have to put up with the hire companies providing kit that could well kill someone.
The answer is you should not.
IF you have had shocks off hire kit then it is not fit for purpose and the hire company are breaking several laws and obtaining money by deception, that is fraudulent, or you are "playing" with things you should not be in ways you should not be.
Either way laws are being broken and peoples lives are at risk, why, in this day and age, when these things are so easy to avoid is such a situation seen as acceptable.


BTW, sorry for the digression from the original thread.

Usually down to a cavalier attitude to safety, one that I try and correct where I can. My personal preference is no RCD in the workshop due to my IT background, I've lived in houses with no RCD's all my life, and I'm still alive after all That said, any system I design will either have RCD protection, or where possible, individual RCBO's on every circuit, so a fault on one does not take the rest out!

We saw a big push towards RCD a while back, leading to situations where houses had the lights also powered by the RCD. That has now changed with split boards, but the simple fact is, sometimes safety devices create problems that have unintended consequences.

Digression is the nature of the net, and I'm sure anyone reading our debate will learn from it.

 

[brightspark]

[quote="Cyberprog, post:
We saw a big push towards RCD a while back, leading to situations where houses had the lights also powered by the RCD. That has now changed with split boards, but the simple fact is, sometimes safety devices create problems that have unintended consequences.

Digression is the nature of the net, and I'm sure anyone reading our debate will learn from it.[/quote]lights are still fed through rcd .the older split boards where the lights were fed from a mainswitch and sockets through the rcd are no longer allowed in domestic supplies u have to fit 17th edition twin rcd board now and split the wiring acordingly so therers allways either lights or sockets working at any time on each floor

 

[Sidewinder]

Cyber,
IF I ever fit domestic DB's I fit "true" double pole RCBO's to each circuit.

I don't do much if any domestic though as it is littered with idiots who are part qualified and charge peanuts.

I have professional overheads to cover so that is not the arena that I choose to work in, unless it is well paid, or a favour.

If you look at BS7671 then you will find several issues that are not overcome with even split boards, a poor attempt at meeting the requirements IMHO.

I appreciate that you are willing to accept my blunt opinions and I respect you for that.

 

[Sidewinder]

[quote="Cyberprog, post:
We saw a big push towards RCD a while back, leading to situations where houses had the lights also powered by the RCD. That has now changed with split boards, but the simple fact is, sometimes safety devices create problems that have unintended consequences.

Digression is the nature of the net, and I'm sure anyone reading our debate will learn from it.

lights are still fed through rcd .the older split boards where the lights were fed from a mainswitch and sockets through the rcd are no longer allowed in domestic supplies u have to fit 17th edition twin rcd board now and split the wiring acordingly so therers allways either lights or sockets working at any time on each floor[/quote]

Not quite brightspark,
A dual RCD board is not compulsory, it is another marketing attempt, not by yourself I agree, but by the corporates to suggest that it is an acceptable solutoion to meet the current version of BS7671 which, if you, really, look into it, it is not, I am sure you will agree?

 

[brightspark]

http://www.tlc-direct.co.uk/Technical/DataSheets/Hager/Hager_17.pdf

 

[Sidewinder]

Bright,

Please don't believe the crap that manufacturers spout, it is only in their interests.
I have not even read this, it is NOT BS7671, nor is it guidance from the IEE (IET), nor even from one of the scams, so is no defence, nor would it be acceptable as evidence in a court of law in the event of a legal case.
Please realise that I have worked in a formal technical capacity as a professional engineer for a global electrical equipment manufacturer.

Ask yourself, are Hager RCBO devices two pole, then see if you still feel that this is a suitable solution where all live conductors must be isolated in the event of a fault...

 

[Cyberprog]

lights are still fed through rcd .the older split boards where the lights were fed from a mainswitch and sockets through the rcd are no longer allowed in domestic supplies u have to fit 17th edition twin rcd board now and split the wiring acordingly so therers allways either lights or sockets working at any time on each floor

Ah yes, they are dual RCD now aren't they. Still, a better solution than a single RCD for the lot!
I have a board here at work with a horrible RCBO, takes up two MCB slots, which would be fine on a single phase board, but on a three phase one is a pain!

Here's my main pet peeve when working in colleges and such on balls - their sparks have gone round and fitted 30mA RCD's to every external socket. Yes kids, the stage has just gone dark and we've now got to run around with our torches back to the distribution point to reset the 30mA RCD, all because the hog-roast guy decided to chuck a load of water over his sockets... arg!

 

[BrokenBiker]

id rather have to flick an rcd back on than evacuate a burning building full of kids...

 

[Cyberprog]

I'd rather the 30mA RCD on the box by the hog roast went first, then the 100mA on the stage distro, before finally a 300mA one at the distribution point!

 

[Sidewinder]

I'd rather the 30mA RCD on the box by the hog roast went first, then the 100mA on the stage distro, before finally a 300mA one at the distribution point!

The thing is Cyber, that won't happen unless you have selective RCD's all RCD's 30/100 & 300mA if instantaneous in design will not trip in the manner you suggest.
The only way what you would like to see can happen is if you have a 30mA instantaneous device at the extreme point, your hog roast, then an S type 100mA at the DB then an adjustable 300mA at the intake.