Terminate SWA at the top of a cast iron lamp post

[malcolmchisholm]

I have come across a cast iron lamp post fed by SWA up through the middle of the post to the top. I have connected the steel armouring to earth (it was not previously connected) back to the DB. At present, the armouring is not connected to the post, but the cpc is crudely terminated to a screw on the post.

Does the armour have to be connected to the post as well as the cpc?

If so, is there a small gland or other device that can be used to connect the armouring to a wire to terminate on the earthing screw o the lamp post?

Many thanks,

Malcolm Chisholm

 

[SPECIAL LOCATION]

Hello Malc....

Interesting first post question...

What is the earthiung type?

is the question wot comes to mind first....

But I am getting a little intoximicated at the moment.....

:BlushingGuinnessO)

]

 

[Evans Electric]

Normally SWA is glanded at both ends but in your case I imagine that is not possible . Armour needs to be earthed at one end at least. Lamposts to be wired in SWA need a control gear section at the base but if they don't they are best wired in split concentric .

Trouble with the open armour wires is they will subject to corrosion , although you say there is an earth conductor in the cable.

Could you not gland the cable off into a galvo through box and lose it inside the post and come out of it with flex.?

---------- Post Auto-Merged at 00:04 ---------- Previous post was made at 00:03 ----------

Oh welcome to the Forum Malc.

 

[steptoe]

what level of expertise/experience ar you at Malc?

there are a few methods of sorting this, would be good to know what one of them you are up to doing though.

---------- Post Auto-Merged at 00:21 ---------- Previous post was made at 00:06 ----------

right Malc,

Ive read your other post,

and as you already have a core of the SWA for a cpc IMO the easy simple way of doing this for a single cable termination is as follows,

trim back the armour to the same level as the outer sheath, leaving the inner sheath longer,

then simply heat shrink some sleeving over the inner,armour,outer sheath as it were to make it weather-proof(as such),

if you get what I mean,

 

[roys]

How about gland it, put an earth frying pan on it (with lock nut) and then nut and bolt the smaller hole on the frying pan to earth along with your earth core. As Steps says there is a few ways of doing this.

 

[Andy™]

How about gland it, put an earth frying pan on it (with lock nut) and then nut and bolt the smaller hole on the frying pan to earth along with your earth core. As Steps says there is a few ways of doing this.

piranha nut does a better job

 

[roys]

[quote name='Andy

 

[Evans Electric]

Interesting that Roys calls them "Frying Pans" which I like, we always call them "BanJos" !! ( Earth rings I'm on about)

 

[malcolmchisholm]

In answer to Special Location, the earthing is TT. I have terminated the SWA back to the earth bar in the DB. Earth loop is approx 90 ohms.

I have glanded a dozen or so SWA cables so far in my career (18 months), but there is a lack of space in the lamp head and no firm fixing to attach it to. There is no access hole at the bottom of the post. The SWA comes from the ground straight up to the head of the post. It was installed many years ago, with no earth connection to the SWA. I had to re-terminate the DB end of the cable to earth it.

The head of the lamp post (the glazed top) looks like an old-fashioned gas lamp and is very heavy. I'd rather not have to remove it.

If I have to take it off, I could gland the end as suggested by roys, using a banjo for the earth connection to take to the terminal on the post.

Thanks for the suggestions. Any more thoughts will be greatly appreciated.

Malcolm

 

[Evans Electric]

I think you'll have to remove it ,Malcy, to see how its connected in there .

 

[kerching]

Some underground BICCAST type joints had a split ring [A BArrymore] which you put under the armour and over the inner bedding. Then you fitted the earth wire to the swa with a jubilee clip. That way the jubilee clip did not crush the armouring which was always the issue. In an emergency I have used a piece of copper or brass tube instead.............. :coat

 

[steptoe]

ah,

a 'constant pressure spring' type of arrangement then kerch.?

the advantage of a CPS is you dont need access for maintenance ALA screw connections.

resin joints use CPS connections.

 

[malcolmchisholm]

Sorry, Steptoe, but what is cps? I'm still learning.

Thanks,

Malcolm

 

[Andy™]

constant pressure spring. also known as constant force spring

 

[malcolmchisholm]

And is this type of spring suitable for terminating on the SWA armouring?

Malcolm

 

[Andy™]

in a resin joint it is. can be used on other cables too- i.e attaching earth to lead service cable

 

[M107]

Weeeelll (and I have been on the merlot) due to lack of space at the post head, I'd terminate to a gland & use a earth nut (Piranha) instead of a banjo & fly lead to post.

But if the supply is TT & swa is connected to met.... does the post need connecting to met via the armour ?...........merlot makes me ask such questions....I should know better:Y

 

[steptoe]

in this situation I dont really see the need to have the armour terminated at both ends, there is a cpc within the cable itself, and it is only one fitting, no loop out to another cable.

 

[M107]

Stepsd is on my wave length (23:17)

 

[kerching]

ah,a 'constant pressure spring' type of arrangement then kerch.?

the advantage of a CPS is you dont need access for maintenance ALA screw connections.

resin joints use CPS connections.

Wasn't a CPS more of a split tube then went between the armour and the inner bedding. This spaced the swa away from the bedding then the jubilee clip sandwiched the earth wire onto the armour and the ring stopped it squishing the bedding. Harder to explain, I may be able to find some left over from my jointing days, and then do some pics...... :coat