Thoughts please, SWA vs T&E

GBDamo · Aug 10, 2022

I have a TPN board that will feed 8-10 sub boards. The loads on each board are negligible 5-10 amps peak but mostly 1-2 amps.

The distribution circuits will be fed in 6mm mostly for VD reasons but also to allow some selectivity on the OCPD(MCB) my dilemma is SWA or T&E.

The route is 98% tray before entering a room and feeding a surface mounted consumer unit.

For aesthetic reasons they want the cables in the wall, fair enough, but I'm in a catch 22.

If SWA I'd never be able to gland into the back of the CUs and the SWA would end up surface, if T&E the cable would be in a timber partition but less that 50mm deep thus requiring RCD which completely negates the principle of sub devision of circuits.

1, Am I going OTT worrying about this c0.5m drop from the ceiling to the back of the CU?

2, My "Solution" is to mount a galvanised box above the ceiling, gland the T&E through into some earthed steel flexicon, down inside the wall and into the back of the CU.

3, Am I missing a more obvious simpler solution?

Thanks.

DPG · Aug 11, 2022

GBDamo said:
It's that thinking that has stiffed the west, the "one death is too many".

Progress requires risk, if you take zero risk you get zero progress. But, and its a huge but, there is a ballance.

I'd further berate the zero risk advocates on account of their hypocrisy, it's not zero risk they want it's zero visible risk, they're happy to profit from heavy industry in India and China, they can't see those deaths.

No one is advocating sending kids down a mine, we'll unless they're brown kids in an African mine, but that's acceptable because, well, I'd have to change my iPhone less frequently.

I've always found it odd the places we don't apply the "One death is too many" rule. Why do we allow leisure use of the roads? How many cyclists die every year whilst playing on the roads?

Swimming in the sea, lakes and rivers; ban them.

Motorcycles; ban them.

Smoking, drinking, sex; ban them all.

You'd be bored to tears but you'd be safe.

Look at the 'Vision zero' scheme.

Dustydazzler · Aug 11, 2022

Watch Demolition Man

Ban anything and everything that may cause an injury or that is bad for your own health

sparkymark77 · Aug 11, 2022

I’ve had this dilemma before and done various things included those mentioned before. For a t&e I ran it in 25mm steel conduit with a terminal box on the end, then earthed the terminal box to the cu earth bar. Made sure the screw in the terminal box was accessible through the knockout at the back of the cu. For swa just take it in to the back of the cu and put the armouring in to the earth bar if it needs to be accessible. If not I agree that terminating the swa into a box behind is nearer and looks more professional!

UNG · Aug 11, 2022

GBDamo said:
It's that thinking that has stiffed the west, the "one death is too many".

Progress requires risk, if you take zero risk you get zero progress. But, and its a huge but, there is a ballance.

I'd further berate the zero risk advocates on account of their hypocrisy, it's not zero risk they want it's zero visible risk, they're happy to profit from heavy industry in India and China, they can't see those deaths.

No one is advocate sending kids down a mine, we'll unless they're brown kids in an African mine, but that's acceptable because, we'll, I'd have to change my iPhone less frequently.

I've always found it odd the places we don't apply the "One death is too many" rule. Why do we allow leisure use of the roads? How many cyclists die every year whilst playing on the roads?

Swimming in the see, lakes and rivers; ban them.

Motorcycles; ban them.

Smoking, drinking, sex; ban them all.

You'd be bored to tears but you'd be safe.

We have to accept that living is dangerous some of the fittest and heathiest people I have known have died way before they should, life is a lottery and when your number is up that is it IMO
We work with electricity and it can be dangerous so why do we do it, more to the point why does anyone meddle with electricity should we ban it, not sure that would go down too well although it would reduce bills

The trouble these days some people have found the risk before even identifying the hazard

davesparks · Aug 11, 2022

GBDamo said:
I've always found it odd the places we don't apply the "One death is too many" rule. Why do we allow leisure use of the roads? How many cyclists die every year whilst playing on the roads?

Swimming in the sea, lakes and rivers; ban them.

Motorcycles; ban them.

Smoking, drinking, sex; ban them all.

You'd be bored to tears but you'd be safe.

How many deaths aren't too many then?

Why shouldn't we strive to prevent deaths on the roads?

DPG · Aug 11, 2022

davesparks said:
How many deaths aren't too many then?

Why shouldn't we strive to prevent deaths on the roads?

It's not that, it's the fact that things like 'Vision Zero' strive to reach an unattainable target. As people have said above, there will always be deaths no matter what you do to mitigate them.

GBDamo · Aug 11, 2022

davesparks said:
How many deaths aren't too many then?

It's a really good question but ultimately its unanswerable. Zero is impossible, millions is unacceptable.

The safety industry, like the racism and sexism and LGBT industries, has won all the major battles. Its the same with any process improvement initiative, they deliver mesurable and meaningful results at their inception but quickly the results drop off as the cost, effort and inconvenience increase exponentially.

But, back to acceptable numbers, this is not an alien concept. Look at the Covid, or any, vaccine. It's known that a certain number of people will die as a direct result of the vaccine but many, many more will be saved.

It is a calculation that already exists.

It's an often quoted truism that changing a light bulb in the NHS costs £75, how much of this is down H&S, Approved Contractor status, DBS checks. All for vanishingly small risks.

Not just light bulbs but all other services carry the Safety surcharge, how many more lives could be saved by the NHS if they weren't spending money trying to avoid otherwise miniscule safety risks.

davesparks said:
Why shouldn't we strive to prevent deaths on the roads?

We should, should we ban driving to achieve it?

James · Aug 11, 2022

It is the law of diminishing returns, at some point, all the effort you put in to make one thing safer is wasted as it only saves a few lives per year.
resources might have been better spent by improving road safety around schools instead (for instance)

GBDamo · Aug 13, 2022

Picture of inside the Bill bus bar chamber.

[ElectriciansForums.net] Thoughts please, SWA vs T&E

Can't remember who wanted it but here it is.

westward10 · Aug 13, 2022

Wasn't expecting that those latter Eaton clamps may well fit in fact they almost certainly will if you get the correct size. This should be on the other thread.

davesparks · Aug 13, 2022

Oh, you do need the MEM clamps after all then!
Get two sets so you can seperate those lugs onto their own clamps. It might just be me but it annoys me seeing stacks of lugs on the same busbar clamp like that.

westward10 · Aug 13, 2022

davesparks said:
Oh, you do need the MEM clamps after all then!
Get two sets so you can seperate those lugs onto their own clamps. It might just be me but it annoys me seeing stacks of lugs on the same busbar clamp like that.

Couldn't agree more.

Thoughts please, SWA vs T&E

GBDamo

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DPG

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Dustydazzler

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sparkymark77

UNG

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davesparks

DPG

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GBDamo

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James

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GBDamo

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