Overhead SWA Supply

[Richard]

Good afternoon, Hope everyones well!

Quick question.

Running a 60A sub-main top adjacent barn about 40 odd meters away. I'd naturally prefer burying the cable however the client would rather overhead. I'v only ever suspended T+E cable on a catenary set-up. Is there any reason an SWA can't be run in this fashion? Obviously there'll be poles at intervals because of the span and weight, but i'm thinking in long term wear/movement damage to the cable.

Thank you for any advice.

 

[telectrix]

tell the client overhead =fathead. you are the expert. insist it's buried.

 

[davesparks]

Id be inclined to use a flexible cable in preference to SWA if it's possible.
One cable you certainly should not be installing on an outdoor catenary is T&E.
When designing the catenary you will need to work out the tension that will be put on the fixings and the amount of sag which needs to be allowed in the wire.

 

[Leesparkykent]

......

 

[Breeze]

Don't forget to get your anchors tested first

 

[Octopus]

Good afternoon, Hope everyones well!

Quick question.

Running a 60A sub-main top adjacent barn about 40 odd meters away. I'd naturally prefer burying the cable however the client would rather overhead. I'v only ever suspended T+E cable on a catenary set-up. Is there any reason an SWA can't be run in this fashion? Obviously there'll be poles at intervals because of the span and weight, but i'm thinking in long term wear/movement damage to the cable.

Thank you for any advice.

Go back to the suspended T&E and change it for a more appropriate cable?

 

[Richard]

When designing the catenary you will need to work out the tension that will be put on the fixings and the amount of sag which needs to be allowed in the wire.

Thank you for your reply.

I'v personally never recalled seeing much guidance on this. Is there any guidance readily available?

Thanks

 

[telectrix]

think the guidance you seek has just been posted.

 

[shanky887614]

Id be inclined to use a flexible cable in preference to SWA if it's possible.
One cable you certainly should not be installing on an outdoor catenary is T&E.
When designing the catenary you will need to work out the tension that will be put on the fixings and the amount of sag which needs to be allowed in the wire.

whats wrong with swa? you can get it with catenary wire incorporated in the cable

 

[telectrix]

whats wrong with swa? you can get it with catenary wire incorporated in the cable

so that's what the 3rd core is for. i always thought it was a cpc

 

[Fin170]

i always thought it was a cpc

No that's what the armouring is for

*runs for cover*

 

[richy3333]

Go back to the suspended T&E and change it for a more appropriate cable?

I was just thinking, that's not the sort of thing you would admit to doing!

 

[7029 dave]

If you are going to fly the cable, remember if it's going over hard stand, it's still classed as vehiclelar access. 5.2 minimum

 

[davesparks]

whats wrong with swa? you can get it with catenary wire incorporated in the cable

Nothing is wrong with SWA, but the steel makes it somewhat heavy, an unarmoured flex will be lighter and obviously be more flexible.

 

[davesparks]

Thank you for your reply.

I'v personally never recalled seeing much guidance on this. Is there any guidance readily available?

Thanks

The cable manufacturers data sheet will give you the mass/metre of the cable, similarly the mass/metre of the catenary can be obtained.
Then you use the physics you learned at school to calculate the tension on the catenary and forces exerted on the fixings.
You can select suitable fixing using this information, but also taking in to account the strength of whatever you are fixing in to.

I have seen the whole top corner of a house ripped away by a DNO overhead when a tree hit the cable!