twin & earth at sea

[SparkyTris]

What is the correct technical designation for "Normal grey twin&earth" cable?

is it suitable for use in boats/ships/cars/caravans?

if not, why not?

in which conditions/environments is it designed for use, and why?

 

[flyingsparks]

No, in vehicles boats etc flex is used as the movement of the vehicle can cause the connections of t&e to break off as it isn't flexible.
T&e is for houses etc which don't move.

 

[securespark]

I've always known it as PVC/PVC Flat Twin/ Triple and Earth 6242Y (+H if Harmonised) or 6243Y (+H if Harmonised).

I would say it is not designed for use in environments subject to movement, vibration etcetera...

It is designed for fixed wiring because the cable is not designed for movement.

Statics are wired with T&E but spend most of their life not moving. I appreciate they are moved within and between sites but I would always recommend an inspection takes place after such transit.

EDIT:

Dayum! Curse you fs! I'm too slow....

 

[PrenticeBoyofDerry]

I believe the standards state, that T&E is for lighting and power circuits for domestic and light industrial buildings.

 

[davelx]

No, in vehicles boats etc flex is used as the movement of the vehicle can cause the connections of t&e to break off as it isn't flexible.
T&e is for houses etc which don't move.

Not just any old flex, especially at sea - it should be made from tinned copper to reduce corrosion.

 

[ban-all-sheds]

I believe the standards state, that T&E is for lighting and power circuits for domestic and light industrial buildings.

[RINGS BELL AND]

Oh.

Don't lights use power?

[/RUNS AWAY]

 

[securespark]

Blame the PEL 64 bunch.

 

[JohnW2]

Don't lights use power?

I don't think it's strictly correct to say that anything "uses" power (any more than it is strictly correct to say that anything "uses" speed/flow etc.), since it's a rate - but I have no doubt that lights "use" electrical energy in the sense that they convert it into to other forms of energy!

Well, it is Friday evening

Kind Regards, John

 

[Spark123]

Not to forget at sea the cables may need to be fire retardant too.

 

[JohnW2]

Not to forget at sea the cables may need to be fire retardant too.

Does sea burn?

Kind Regards, John

 

[ban-all-sheds]

Yes.

But only when there is nobody there to see it.

 

[mfarrow]

Does sea burn?

If you pour it onto a fire involving wire wool, yes it does.

 

[ericmark]

The answer to question is simply no it's not suitable for boats however the boat I was involved in the wiring used what seemed to be standard SWA cable with Hawk glands. Plus seals in every bulkhead and these bulkhead seals did need round cable.

The Schiehallion

may be a little larger than you are talking about with smaller boats bulk head seals may not be as important.

My sons narrow boat was wired in flex but I seriously don't think it flexed much. 1/4 steel plate does not tend to move. Older wooden narrow boats will flex often they need tie bars to stop them becoming wider than the locks will take.

As to lighting and power this is historic, when houses first were supplied with electric the lighting used a different meter to the rest of the power and to persuade people to use electric lighting which was safer than oil, gas and candles the lighting power was charged at a lower rate to other power. So the phase lighting and power was born. The cables were sheaved in lead and when the plastic cable twin and earth was made the outer was made in the same colour as original lead as with the lead one had an earth available it was the old rubber cables (black) which had no earth although there were exceptions.

So it is possible with some ships/boats they would use twin and earth cable it would depend on the construction.

One thinks of a wagon being rigid yet I have seen where a 8 leg tipper has tipped sidewards yet the cab is still upright the chassis being twisted through 90 degrees. It is hard to envisage how much movement structures go through so I personally would use flex to be on safe side.

 

[JohnW2]

My sons narrow boat was wired in flex but I seriously don't think it flexed much. 1/4 steel plate does not tend to move.

Isn't vibration etc. also an issue, as well as frank 'flexing'? My understanding (perhaps wrong!) was that in anything which (unlike a building) 'moves' (any sort of vehicle, ship/boat or aircraft) one should use flex, even if flexing, per se, is not a significant issue.

Kind Regards, John

 

[ericmark]

I will admit vibration can be a problem with steel structures. I remember with a concrete batching plant we had to regularly test terminal tightness when the maintenance free terminals arrived in the 1980's it really reduced our work.

However although the house may have brick walls the floors are generally wood which likely vibrates and flexes it is hard to quantify how much vibration and flexing any structure has. We don't ban the use of audio equipment in the home which must cause vibrations.

A caravan clearly both flexes and vibrates be it a mobile home or touring caravan but we still use twin and earth in mobile homes. Not really sure why I would think even with a mobile home we should use flex but we don't.

So road vehicles are clearly flex but with other vehicles it is harder to draw the line. I would not expect vibration on a butty narrow boat but with one using a Lister ST1 then one would expect vibration.

One has to use some common sense there can't be a one size fits all answer.