over-use of SWA

[Steve]

Why is SWA used so extensively in commercial applications, where t+e would be sufficient?

For example, we have 3 air con compressors outside at our shop. The supply for these is 3 separate SWA cables running from the main DB through 3 isolators inside, then out to the units. Most of the run is inside, above a false ceiling, and inside trunking (the armour is terminated on the metal trunking, which runs beside the DB) I would call this run pretty well protected, and dont see why SWA is required, apart from between the isolators and the compressors outside, especially for 3 long runs of the stuff.

Linking 2 distribution boards together: a loop of chunky SWA is used underneath them. They are right next to each other! Wouldn't a conduit and single cores / meter tails be more appropriate?

Linking a compressor to its remote dairy chiller: All the current it carries is for 6 fluorescent lamps and a few fans and thermostats (supply actually comes from a metaclad wylex re-wireable fuse box). Why is SWA used here?

All this seems like money wasting exersizes to bump up the cost to the commercial client: because they can afford it.

 

[Big_Spark]

Crafty, despite what you may think, it is often cheaper to install using SWA than other forms of cabling systems.

It is usually quicker in terms of man power, and uses less materials as the protection of the cable is built in.

 

[Lectrician]

I HATE the abundant use of T+E on installs.......

In a commerical application, galv trunk, galv/pvc conduit and swa are the route to go.........

In a shop, yes, T+E where protected by ceiling void etc, and above false ceilings (even then, usually on tray!).

It is the DIY'ers in my opinion that chuck FAR TO MUCH T+E in. How many barns do you see with T+E clipped?? I HATE it.

 

[Darkness]

Might be alot of T&E used in barns but alternatively using singles and conduit isn't the quickest or easiest at times and can work out just as expensive.

I've recently seen places with swa used when T&E in conduit would have been a much cheaper option.

 

[Adam_151]

Agree with the posts by big_spark and Lec,

also T&E above a certain size, say 6mm² gets cubersome to work with, especially when making corners, if you have to make a corner along the bigger axis of the cable, the min bend radius is going to be quite big, swa, being round means the bend radius doesn't depend on which way you are bending it.

 

[Big_Spark]

I've recently seen places with swa used when T&E in conduit would have been a much cheaper option.

I have never known any installation where the cost of SWA would exceed the cost of installing Conduit and singles.

Conduit and it's fixings have a price that exceeds the cost of all but the larger SWA's, further the labour costs of installation increase as well, then you have the labour costs of wiring the conduit.

I am sorry, but having been doing this Job for 22 years, and having priced thoursands of jobs in that time, there is no way you will ever convince me that SWA is more expensive that conduit and singles.

The installation method should be suited to the environment.

 

[delmel]

Price is the key, and most Air con installations are done in SWA