Volts Between N And Earth

[DirectFS]

Hello Bill... lots of good stuff but I wasn't after an explanation of EFLI... just trying to get across that if the OP understands the paths that current can take to get to earth then he might better be able to work out the solution to the potential problem.

And the fact that in order for the overcurrent device to operate (not an RCD) then in some way shape or form their must be a fault path involving the particular phase conductor entering the property and eventually passing through the "fuse" protecting the sub-circuit.

As has been said... a lot depends on the method of distribution/earthing arrangements of the particular property.

Understood.

It ultimately does come down to the supply and installation earthing methods.....

And this is one reason I think the 17th's emphasis on RCDs, split loads, RCBOs and so on is going to come back and bite many a so called designer on the ass.

The whole of the UK is still a way away from having a fully PME'd network.

A lot of electricians have no idea of how to identify, and rectify earth faults. I suppose that's true for many "fire" engineers too, though.

I've seen RCD's bypassed, or simply removed, because of earth faults - and also, 100mA rated trip current RCDs put in, replacing the "safe" 30mA.

You have to wonder what these people are thinking, given that it only takes 15mA of current to seriously damage a body, and under 30mA will almost certainly ensure death......yet they're bypassing the very device that offers the protection against this.

Tieing this into the thread about standards, variations, and so forth - I'm coming to an understanding that part of the problem is education in the first place - something obviously allows people to think they *can* get away with it, so they *do*, assuming it to be standard practice.

Who thinks that even trade qualifications are dumbed down these days - apart from knowing the industry itself is (as in replacing boards without proper investigation, no longer replacing components etc.)......

Bill.

[esp-protocol]

You're right....

A lot of the older sparks I've worked with will install 6mm cable to a cooker... regardless..... because "that's what I've always done and there's nothing wrong with it"...

They've never heard of diversity/load factors etc.... or realised it's a gas cooker.......

[DirectFS]

You're right....

A lot of the older sparks I've worked with will install 6mm cable to a cooker... regardless..... because "that's what I've always done and there's nothing wrong with it"...

They've never heard of diversity/load factors etc

And showers......

It is a problem though. Many times, an electrician will run a specific circuit, in a specific CSA, irrespective of design. For example, a final ring main - 2.5mm CSA, irrespective of distance from sub main, irrespective of any rating factor - even if it should be 4mm CSA.

Another problem in that respect is pulling a high load single phase, say 26A, along a cable buried in the wall, or ground - and wil lstill use 2.5mm CSA, because they think "less than 30A (32A these days) - 2.5".....no regard to the fact that when you bury PVC sheathed cable, you need to start allowing for factors such as heat, fire risk, and so on.

Though I think this has as much to do with complacency as it does a lack of education. It is, I suppose, also a product of the "lessening" of electrical and other trades - the notion that there's no real skill or specialist knowledge behind what a lot of them do.....

Bill.

[james.wilson]

agreed and some of the newer badges infer all this knowledge and training of 236.

[luggsey]

Who thinks that even trade qualifications are dumbed down these days - apart from knowing the industry itself is (as in replacing boards without proper investigation, no longer replacing components etc.)......

It's happened because apprenticeships have been overlooked for the last ten or more years.

The thought of doing a job with both manual and technical work involved seems to frighten the 'console kids' of the last few years to the point at which there are not enough trained people. The reaction is to produce 3 week sparkies and dumb down everything to such a level 'anyone' can win! Result, well c##p in c##p out!

As for replacing components, how about this, when I was servicing it was more expensive to replace ni-cad cells in a emergency light then to install a new one. Upside down world or what!

[esp-protocol]

It's happened because apprenticeships have been overlooked for the last ten or more years.

The thought of doing a job with both manual and technical work involved seems to frighten the 'console kids' of the last few years to the point at which there are not enough trained people. The reaction is to produce 3 week sparkies and dumb down everything to such a level 'anyone' can win! Result, well c##p in c##p out!

As for replacing components, how about this, when I was servicing it was more expensive to replace ni-cad cells in a emergency light then to install a new one. Upside down world or what!

That's true.... what bugs me these days is how hard it is to find a spark under 35 that can terminate an MICC......

[james.wilson]

lol true

but IMO the whole apprentice thing is dead in the water.

Back in the day the bigger firms did the training, as they had the margin etc to be able to afford it,and they needed they guys.

Now because of 'progress' they cant anymore and it was the first thing to get cut, ie training programmes.

GRanted they still train but not to the level they did.

We used to do system on the boards traning centres. All closed now.

ALso the expectation of the 'trainees' is higher. They want 40k and a 10 hour week within the first 3 months.

When i did my electrical it was 3 yrs minimum.

Took 2 yrs to be classed as a 'qualified mate'

New schemes allow full qualification in days. granted in limited scope but still. When i was at college doing my 3 yrs, a plumber could do an acops course (think it was acops) and then terminiate showers, cookers, boilers etc, yet i couldnt touch anything on my own.

We are going way off now but while the market is 'open' then market forces will rule. We have proved that self regulation doesent work in any market. But would enforced regulation stop the cowboys etc? The consumer is offered various approval options in every market. Do they choose these options? some times.

Also should we allow a choice? nanny state etc. Going back into the past in or own trade its was ahrd to start up a company. There were a lot of hoops that needed finacial backing to attain. These requirements were loosened rightly or wrongly. Are we in a better position as an industry than we were 20 yrs ago. I think not but I also think we are not alone. All industry suffers the same. The answer may be licencing i dont know. Id like to know how its going in ireland, is it working there. WHat are the problems if any? Or has it been a waste of time that hasnt solved anything?

[steven sneddon]

That's true.... what bugs me these days is how hard it is to find a spark under 35 that can terminate an MICC......

1 in 10 so called "fire guys" up here can make off an end (MICC)