Outside electrics - WD40 to stop water ingress?

Hi,

We have some 240v tree lights outside - a few heavy duty sets which are des= igned to stay out there all year. From time to time they get dim, and the p= roblem is caused by small amounts of moisture getting into the electrical j= oints between the power lead and first set, and similar joints between sets= of lights. The joints seem tight and well-designed with O rings, but over = time water does get in. (The three pin plug itself is fine, it's in a prope= r outside socket.) The problem just means that every now and then I have to= open up the joints in dry weather to let them dry out, and abrade away any= corrosion.

Question: is there anything I can put/spray into the joints that would help= to stop this from happening? I'm thinking of WD40, but I've read that it c= an degrade plastic over time, and the joints are plastic.

Cheers!

Martin

Reply to
Martin Pentreath
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stop this from happening? I'm thinking of WD40, but I've read that it can degrade plastic over time, and the joints are plastic.

Silicone spray.

Reply to
Grimly Curmudgeon

designed to stay out there all year. From time to time they get dim, and the problem is caused by small amounts of moisture getting into the electrical joints between the power lead and first set, and similar joints between sets of lights. The joints seem tight and well-designed with O rings, but over time water does get in. (The three pin plug itself is fine, it's in a proper outside socket.) The problem just means that every now and then I have to open up the joints in dry weather to let them dry out, and abrade away any corrosion.

stop this from happening? I'm thinking of WD40, but I've read that it can degrade plastic over time, and the joints are plastic.

WD40 does instantly displace moisture, but IME, gives no lasting protection against moisture, so that's probably not what you want. If you want to try this, I would use a product designed rather more for the purpose, such as maybe a spray for waterproofing car ignition leads and distributor caps (remember those?;-) Holt's Damp Start was one such, but it may not have existed for years for all I know.

You could fill voids in the connectors with resin, but it obviously mustn't get into the connector mating area. It's a once off do-or-die type operation though, in that if you do this and water still gets in, the connector will not be repairable.

For O-ring and other seals, a light smear of silicone lubricant can help (the type used for plastic pushfit plumbing).

Given the repeated failure of your connectors, maybe it's time to replace them? I have an in-line waterproof cable connector outdoors which has been there for ~7 years, and has never caused any problems. (I haven't actually opened it and looked inside, but it's powered

24x7, and hasn't ever tripped the RCD.) It's marked IP65, 16A, and quite small/slim, but I can't see a manufacturer's name on it. It came from B&Q, but that was before they made way for the cushions and sfa throws, so they might not do it anymore. It's important the cable glands correctly fit the cable in use, and that might be difficult with the oval/flat cable often used with insulation piercing lampholders used on lighting strings.
Reply to
Andrew Gabriel

In article , Martin Pentreath writes

If you want a maintainable (dismantleable) joint I'd say new choc block packed with petroleum jelly (vaseline). Apparently avail in generic form in a little tube from the chemist which would probably be ideal for squeezing into the connectors in a grease gun stylee.

Reply to
fred

esigned to stay out there all year. From time to time they get dim, and the= problem is caused by small amounts of moisture getting into the electrical= joints between the power lead and first set, and similar joints between se= ts of lights. The joints seem tight and well-designed with O rings, but ove= r time water does get in. (The three pin plug itself is fine, it's in a pro= per outside socket.) The problem just means that every now and then I have = to open up the joints in dry weather to let them dry out, and abrade away a= ny corrosion.

lp to stop this from happening? I'm thinking of WD40, but I've read that it= can degrade plastic over time, and the joints are plastic.

I'd make a more suitable connection, such as soldered or perhaps crimped. If you go with grease, petroleum jelly is the only type that should be used on electrical connections, others become corrosive when electricity is applied. Resin potted connections are another option.

NT

Reply to
NT

Well, I used to use Dampstart but then my joints were not plugs but choccy blocks in boxes. I guess its stopping the water ingress in the first place.

Brian

Reply to
Brian Gaff

WD40 will probably not have the lasting effect you need. I would suggest a silicone grease since this is plastic and rubber safe:

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Reply to
John Rumm

designed to stay out there all year. From time to time they get dim, and the problem is caused by small amounts of moisture getting into the electrical joints between the power lead and first set, and similar joints between sets of lights. The joints seem tight and well-designed with O rings, but over time water does get in. (The three pin plug itself is fine, it's in a proper outside socket.) The problem just means that every now and then I have to open up the joints in dry weather to let them dry out, and abrade away any corrosion.

stop this from happening? I'm thinking of WD40, but I've read that it can degrade plastic over time, and the joints are plastic.

Do the joints need to be dismantled? If not, adhesive lined heat shrink sleeving should keep any water out. It has been protecting some of my outside electrics in a pit that fills with water from time to time for more than a decade now. A few layers of self-amalgamating tape might be almost as effective and would be simpler to cut off if you do occasionally need access.

Colin Bignell

Reply to
Nightjar

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Reply to
ARWadsworth

Go to a vet suppliers or farm shop and buy a kilo tub for the same price as a ripoff chemist's size. At the same farmers' place, buy a

25ml or 50ml syringe and fill it with Vaseline. The needle is unnecessary. It's easy to squirt some in the connectors with that.
Reply to
Grimly Curmudgeon

Surprised, my experinces with adhesive lined heat shrink is that it's not that good an adhesive and over time comes away from the cable leaving a nice capillary way for moisture. This is on stuff that is disturbed quite regulary though not static.

That would be my choice, easy to cut off should you need to and the best stuff for keeping wet out of electrical cable joints. I had some Tx/Rx cable joints on the roof of a flat for about 15 years wrapped in SA tape. When I took the aerials down and cut open the SA tape over the connectors they were just as they were when installed.

Reply to
Dave Liquorice

Generic is 50p and the chemist is walking distance.

Reply to
fred

In article , harry writes

Bad idea, plastic deformation, loss of contact pressure and overheating.

Reply to
fred

Aha, you don't have ripoff chemists near you. Otoh, I have a very good farmers store. I bought a kilo tub of vet vaseline for a quid (or something ridiculously cheap) ten years ago and have only just used a third of it. Marvellous stuff.

Reply to
Grimly Curmudgeon

Knowing it was likely to be submerged from time to time, I was very generous on the length of overlap at each end - around 10 times the finished diameter - and, as you say, it has never been disturbed.

Colin Bignell

Reply to
Nightjar

They're not bad but they do have expensive stuff in pretty packages in sight for the uninformed. I make them work a bit by asking for generics and stuff in less pretty packages that are generally held only in the pharmacy (although not PoM). They consult with a dusty old price list (which seems fixed by what they are allowed to charge NHS) and frequently check twice when they see how low the price is.

I would like a nice farm supplies shop a bit nearer though ;-)

Reply to
fred

That technique's been discredited for years.

Reply to
Grimly Curmudgeon

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