Laying Electrics and water pipe for outbuilding

[conny]

@SysMax as OBD says, use polypropylene cord of a decent thickness and don't be stingy with the length at each end. I've seen people leave about 12" hanging out the end when, in reality, you need to use at least double the length plus a few feet for grabbing. Then when you have pulled the cable through you simply pull the cord back so it's ready for any more.

 

[SimonH2]

Going by recent experiences at work, telecomms/data cablers seem to have an aversion for leaving one of these in after they have pulled through the cables they need.

There's a good reason actually ...

Use braided rope and NOT twisted rope. Twisted rope untwists under tension and will cause the cable and the steel line to wrap around each other thus rendering the steel line unusable as a future draw cord

And also most cables will twist. So in practical terms, whatever you do, you will end up with the newly pulled in rope and cable twisted together.
AIUI, it's standard practice for the likes of BT (or these days, BT OR) to not pull in a new rope alongside the cable - but they do have large versions of conduit tapes to pull new ropes in as required. The last thing you want when you've hooked up your rope to the capstan winch is to find that you're pulling out a (sticks finger in air and picks a number) 200 pair trunk cable as you pull in your new cable

Interestingly, only recently I had a tour (was there on business) of a place that does custom cables for those with special needs and deep pockets. It was interesting watching the processes building up specialist cables from drums of singles (or coaxes, or Cat6 sets, or optical fibres, or ...) spinning around, through to fully finished cables complete with inkjet printing for identification. They have the facility to apply two layers of wire armour, with opposite twists and carefully calculated steel cross sections, for cables that need to be twist free when put under tension.

 

[Stewb]

Wee tip: a henry hoover sucking away at one end while you feed a cord in at the other should save your bacon if you ever lose/are lacking a pull through.

 

[DetlefSchmitz]

I've always found a fish tape perfectly adequate.

 

[bernardgreen]

And also most cables will twist.

Not my experience when the cable is fed from a reel that can rotate as the cable is pulled off the reel, but a different matter when the reel is not able to rotate and the cable is peeled off the reel

Wee tip: a henry hoover sucking away at one end while you feed a cord in at the other should save your bacon

Works very well.

 

[SimonH2]

Not my experience when the cable is fed from a reel that can rotate as the cable is pulled off the reel, but a different matter when the reel is not able to rotate and the cable is peeled off the reel

I've experienced where the cable can be seen to visibly rotate as you pull it IF the pulled end is free to rotate. Given the construction of most cables, it's more or less inevitable that it will twist if put under tension - untwisting the twist of the cores makes the effective length longer, so that's what's going to happen if it can.
There's a reason you can, if your needs require it, buy both cable and rope that is specifically designed not to twist under tension.

 

[SysMax]

If you had used ducting/decide to use ducting, remember to pull a draw cord through with the cables.
Any upgrade/problem in the future can be quickly sorted by pulling a fresh cable through.
Going by recent experiences at work, telecomms/data cablers seem to have an aversion for leaving one of these in after they have pulled through the cables they need. I find it amusing at their frustration when something goes wrong, and they don't have a spare pair of leads they can use, so they have to try feeding another cable in.
I had to show one guy, (admittedly he was a youngster), how to pull a cord through by using the damaged cable from the source side, and how to attach the new cable a short distance behind the old cable. This way, he got the new cable in and had a cord for any future problems.

Thanks for the advice Conny

 

[SysMax]

Use braided rope and NOT twisted rope. Twisted rope untwists under tension and will cause the cable and the steel line to wrap around each other thus rendering the steel line unusable as a future draw cord

What kind of conduit do I need for buried armoured cable?

What ever duct you use put a rope through it prior to burying, flexi duct comes with a draw wire, but i still prefer using that to pull a more sturdy blue nylon rope in I'm a bit paranoid about it, I'd probably put at least two in if I was doing the work personally :)

www.diynot.com

Thanks for the tips people. Much appreciated

 

[SUNRAY]

Wee tip: a henry hoover sucking away at one end while you feed a cord in at the other should save your bacon if you ever lose/are lacking a pull through.

Yep and always a dam sight quicker than I expect.

Several years ago I was on site to pull 120m 0f SWA and comms into 150mm ducts: https://www.diynot.com/diy/threads/feeding-draw-rope-into-ducting.239087/page-2 post #23 & #29

Henry pulled brickies nylon line in in seconds, as fast as it can be in position to be sucked.

EDIT: good heavens was it really 11 years ago?

Edit2: another site, we'd provided a 150mm duct about the same length in a straight line. Guys arrived to pull in 4C 35mm² SWA and used the lorry to tow it in, of course they tried to do it too quicker than they could feed it and snapped the drawrope. Henry even managed to suck the 8mm polyprop rope the distance but we did need to put a rag on it.

 

[SimonH2]

And I bet they didn't use any pulleys, but just let the rope carve into the duct and manhole edge, as well as be damaged by them.
I've seen winches used (both for pulling cables, and for pulling pipe-splitting moles during water main replacements) which have a "leg" that drops down so that the pull can be straight in line with the duct (or pipe).

 

[john4703]

I had similar office in garden and run plastic heating radiator pipes in ground. About 500mm deep inside 40mm waste pipe. Put small radiator in the insulated shed.

I've thought of doing this but is there a danger of the radiator freezing at night? I'm using electric heating at present but a radiator would be far better. I'd like the view of someone who has done this.

 

[SimonH2]

I would suggest that if you are using a building as an office then it ought to be reasonably well insulated - otherwise it's going to cost a fortune to heat as well as being uncomfortable to work in. A lot of variables, but given an insulated box, it shouldn't get too cold too quickly - so if used daily I wouldn't think there'd be much risk. If only used intermittently, or not used for a while (e.g. while on holiday), then there's a bigger risk. In any case, a frost stat suitably wired would minimise the risk.

 

[Wayners]

If its a really cold spell you just leave heating on low. Turn radiator water temperature down. That's what we did.
Pipes were well insulated in ground but I wanted to keep office warm.
Not my area but you can add Sentinel X500 multi-purpose inhibited antifreeze to heating system if your worried.
Check with heating engineer to confirm.

I was thinking about this option