12 Tips for Large Cable Installs

by Editor on September 24, 2016

Installing large SWA armoured cables can be quite simple if they are simply laid in the ground, but when it comes cable pulls at high level and around bends, things can be more tricky!
Having pulled in several heavy industrial cables recently, ranging from 50sq.mm to 300sq.mm (600MCM), I wanted to share my top 12 tips and experiences for large cable installs.

Pull in Large SWA cables install

The Secret Of Success
It’s all in the planning! When you’ve done all the planning and preparation, and are using the best equipment, actually installing the cables should be the easy part of the job!

Tip 1- Check the drum’s weight and size
Don’t underestimate the weight of the cable and the drum. I recommend always asking your supplier for the weight of the cable plus the drum and also the height (diameter).  This is so you know if you’ll be able to roll it through doors and openings, and also that the cable jacks and steel bar are adequate for the size of cable drum.

 

Tip 2-  Move the cable drum with care
It’s worth checking that the cable will be delivered on a truck with a crane jib so it can be slowly lowered to the ground. In the early days one of our suppliers simply dropped 200 meters of 240sq.mm 4 core SWA straight off the back of a low loader. The weight of the cable (over 2 tonnes) broke the drum which caused us all sorts of problems.

The cable drum will probably be already well used, and a large cable on a wooden drum will creek and the central slats will move as you roll it along. Don’t be tempted to rush into man handling the drum into position and end up twisting and weaking it when turning corners. Turning or dragging a heavy drum of cable to change direction will be almost impossible, no matter how many bodies you have heaving and pushing. Always wear gloves and beware of splinters.

A good tip is to get 4 pieces of steel plate or trunking lid about 400mm x 150mm  and place them (2 each side) under the drum to act as slips. You’ll be surprised how easy a heavy cable drum will slide. You may also consider protecting the floor at turning points with a sheet of plywood.

Tip 3-  Prepare your cable route with care.

Large SWA cables don’t easily go round corners. You can fix cable rollers strategically along the route and at bends, but the more straight runs there are the easier the pull will be. Allow plenty of time to install ladder rack or cable tray where required and use steel channel and angle brackets to make up temporary supports for rollers.

Tip 4-  Use cable rollers and lubricant

Cable rollers placed every couple of metres on straight runs and at snag points will make the job of moving and pulling large cables much easier. Using rollers will also help smaller cables pull effortlessly around bends and over obstacles.

cable-rollers-on-ladder-rack

 

Be sure to secure your cable rollers well and use a good cable lubricant at strategic points on the run.  Especially effective when feeding through cable ducting.

Water based cable lubricants are less harmful to cable sheathing.

 

Tip 5-  Use Ladder Rack

Using sections of ladder rack supported by threaded rod (studding) hangers and steel channel cross pieces makes for a good solid cable installation. Heavy duty cable tray may be adequate for SWAs up to 70sq.mm but ladder rack makes for much more sturdy cable ways.

For difficult high level installs you could consider pulling in the cables first, securing them above your run and then installing the ladder underneath. This would then allow you to drop the cables carefully down onto the ladder. For difficult large cable installations we prefer to prepare the route by installing all the fixings except for the ladder rack, and then pulling in the cables.

Tip 6-  Use a cable sock or Clove Hitch knot

Use the correct sized cable sock over the end of the armored cable for pulling. It will reduce to a nice snug fit on the cable and shape to a point with a loop to attach your winch cable.

If you don’t have a cable sock then good knot for securing to the end of the cable would be a clove hitch (add more half hitches if needed).  The short trailing end of rope can be taped to the cable so as the rope pulls, the tension is increased and the half hitches will tighten around the cable.

Tip 7-  Run a Draw Wire

Run a draw wire or rope over the length of the cable run before starting. This will give you a good idea of how your cables will fall when passing over obstacles and at pinch points around bends.

Tip 8-  Use a good winch and steel cable

The process of pulling in a large SWA cable is normally best taken very slowly. For this reason I prefer to use a hand cable winch like a Tirfor and a steel cable.  Tirfors can be hired and come with a steel cable and shackles for attaching to a cable sock. They are amazingly powerful devices and the manual action allows you the get a feel for how the pull is going in case of snags etc.

We like to pull in large cables very slowly and keep checking at critical points along the route. One man on the winch and others reporting back on progress.

An electric winch probably makes for a quicker pull, but if the cable gets snagged you may not find out until it’s too late. This risks damaging whatever is causing the obstruction, your fixings, or even the cable.

We also  use a couple of smaller 1 ton chain winches which are easily hooked up into position for lifting the heavy cables and pulling out on bends.

Tip 9-  Good Communication

For installing long runs of cables I recommend using walkie talkies for communication. They are relatively low cost and will probably save you a fortune in mobile phone bills. A 3 or 4 way set will allow everyone to hear your commands and let you know quickly when to stop the pull if needed. We used the Mororola T80 Walkie Talkie kit.

Tip 10-Use Cable Benders

When your cable are finally installed and stripped back within their enclosures you’ll need to bend the single cores into position for termination.

Bulldog Bender

Bending by hand is normally easy for anything up to 50sq.mm (0AWG) but things can be made a whole lot easier using a cable bender.

The “Bulldog Bender” is probably the best for anything up to 240sq.mm (500MCM). There’s also a “Big Daddy” for 300 to 400sq.mm (600 to 750 MCM).

 

 

I’ve also found that the simple Rack-A-Tiers 77455 “Bend All”, which fits onto a half inch drive ratchet set shaft, is ideal up to 240sq.mm (500MCM).

Note- Both these items can currently only be ordered from USA and Canada. Delivery takes about 7 to 14 days, but worth the wait!

Tip 11-  Use the right amount of Labour

Employing the right amount of labour for your large cable pull is crucial. Having too many people on the job can be unproductive, waste time and cost you more money. Too few will result in the risk of cables snagging and can be dangerous. You’ll need at least one person on the winch, one at the drum, and enough others to position at each bend or snag point if it’s a long pull. Also someone to make sure the front end of the cable is pulling through ok.

Tip 12-  Work Safe

For saftey’s sake you should always carefully consider how you will proceed with your cable installations. This includes assessing the risks and completing a Method Statement and Risk Assessment which everyone working on the job should be required to read and sign.  This will help all your operatives to work as a team and also cover you should anything go wrong. It’s also important to let others on-site know about your works and any hazards that it may involve along your cable route.

Essentials Kit For Large Cable Installs

  • Winches– For pulling cables your best friend will be a good cable pulling winch or Tirfor- Mount it securely to the floor using ground anchor bolts or to the building’s structure such as a beam or column using a webbing belt and shackle. Chain winches are fairly cheap and are good for lifting and pulling bends in large cables.
  • Webbing belts or strops- Webbings are very strong and adaptable. They have a loop at each end which is great for securing winches, and for making up temporary cable support loops with a shackle.
  • Cable Socks– Cable pull socks help make the joint from the winch to your cables as steamlined and secure as possible.
  • Cable Jack Stands– Make sure that your Cable Jacks and the steel bar are big enough for the drums you’re using. Don’t jack up too high and always stand at a safe distance when “jacking up” and rotating.
  • Good Rope– Check the weight/lifting capacity of your ropes
  • Cable Lubricant- Water based cable lubricant will not damage cable sheath. Lubrication is inexpensive compared to the time wasted in trying to free up a jammed cable.
  • Cable Benders– To bend single cores over 50sq.mm
  • Hydraulic Crimpers and Cutters– Make easy work of cutting large cables and are essential for shaping triangular cables and crimping large lugs.
  • PPE– It should go without saying and I’m sure you’ve heard it before- Don’t start pulling in large cables without the correct PPE gear, this includes decent hard wearing gloves, steel toecap footwear and the rest!

All the best- Steve


ElectriciansBlog.co.uk

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