double ended non insulated crimp ferrules

[ban-all-sheds]

Sounds like just the application for some of those old solder splice techniques documented nearly 90 years ago by the Chicago Engineering Works.

 

[bernardgreen]

otherwise you are reliant on every single joint taking the tension without failure.

There will be a strain relief strand in the catenary so the joint will not be under mechanical stress

some sort of clip to attach the branch wiring,

one tie wrap will do the job

slice the insulation off at the point ~~~ solder

Too labour intensive. I can get the wire machine cut and stripped so a simple crimp joint is the fastest way to assemble them

 

[bernardgreen]

Thanks BAS but that really would be too much work and overkill for this project where there will be 754 joints made by un-skilled labour.
Another thing to consider is that soldered joints stiffen the wire and make it less flexible either side of the joint. As the cantenaries are 9 metres long they have to be coiled up for transport to site and stiffened wires would become a weak point if bent in the coiling up process.

 

[ban-all-sheds]

Can you get vampire tap lampholders of the right size?

 

[bernardgreen]

Can you get vampire tap lampholders of the right size?

Yes but the lamps have to between 1.75 metres and 0.75 metres below the catenary cables. Catenaries are stretched between the beams and most of the lamps have to be below the existing lighting bars which are about a metre below the beams.

 

[Spark123]

I'm a wondering if there will be an issue with the volt drop you are going to get with 2w or 3w lamps at 12v, 30 on two 9m long strings of 0.52mm cable.

How about using larger bare pieces of metal rope, heat sleeve sections of 30mm from one end and feed on terminal blocks between?

 

[bernardgreen]

The cantenary will have 4 wires to make it a "ring" so the wires the lamps hang from will be fed from both ends. Volt drop is un-likely to be noticable in terms of lamp brightness based on previous set ups.

The system has to designed so as to be installed in less than 2 hours after arriving on site. ( preferable one hour ) so string bare ropes is not really an option but has been added to the list of alternates should the trial assembly be a failure.