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External Electric Wire Connections

Posted By: fish5133

External Electric Wire Connections - 29th Jan 2018 5:06pm

Anyone used any proprietary products for waterproofing small external wire connections. Replacing an old security light and the new LED one comes with a short length of prewired flex. Just want to connect this to the existing power supply coming out the wall. Would have used simple connector blocks and a load of insulating tape but anyone used any specific cheap products. Working at top of a ladder so a simple as possible.

Posted By: diggingdeeper

Re: External Electric Wire Connections - 29th Jan 2018 6:08pm

If you do resort to tape, get some self-amalgamating tape, give it plenty of stretch to get it well sealed and I usually put a layer of ptfe over it as well (I wouldn't do this with mains except for a temporary fitting).

In most instances I would replace the short cable with a longer one to place the connection problem inside the property. Just make sure the cable is the same diameter/shape as the old one to use the existing seal.

IP64 (or above) junction boxes are available but getting the right size seals can sometimes be a problem.
Posted By: Habdab

Re: External Electric Wire Connections - 30th Jan 2018 8:36am

If you do have to make an outside join in the cable, drop the level of the cable in a short "U" shape both sides BELOW the level of the joint. The water running along the outside of the cable will drip off at the bottom of each "U", thereby preventing it from flowing into whatever join you were forced to make. It's not a perfect solution but will keep a lot of water away from the connection.
Posted By: Excoriator

Re: External Electric Wire Connections - 30th Jan 2018 9:04am

Security lights are a great boon to burglars. It allows them to plan their entry and exit carefully in adequate illumination without tripping over or leaving footprints. If deemed necessary, they can be taken out of action with an air rifle, but it is usually more convenient to leave them on. I'm not a believer in them, but you clearly are so...

My approach would be to examine the light to see if a longer cable can be easily substituted for the short one that comes with it. Then you won't need a junction box at all, outside at least.

If this is not possible, I suggest you use a small junction box designed for the job. You need one with a rubber 'O' ring to seal the lid, and make sure both connections - power in and power out - get into the box from the bottom so water will not run into the box from above. You don't really need to worry about a seal then. Electrical connections can be made using a terminal strip. You'll need to drill a hole or two to secure the box, but you'll need to drill holes to secure the light too so that's no big deal. I'd use stainless steel screws so you stand a chance of removing them in years to come if need be. Take care on the ladder.
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