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Waterproof connectors that are reliably waterproof

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T

treez

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Hello,

We have multiple LED lamps that will be in a bare room. They are all supplied by 48VDC. There are multiple connectors to each lamp. We need all of these to be waterproof, as the room regularly gets sprayed with a deluge of cleaning water. If any connector is not watertight then the 48VDC bus will get shorted and it will take us ages to find the “guilty” connector that’s leaking. Is there any form of waterproof connector that can be reliably assembled and be definitely waterproof?
These ones just don’t look up to it…
https://www.toolstation.com/shop/p27346
 

Waterproof for "washdown" duty, WeatherPak or MetriPak
automotive connectors are not bad, they have compression
seals for each wire hole and for the two mating shells.

Submersion, now you're talking serious money and I have
no idea about brands.
 

Hi,

I was going to suggest thinking inside the box :) instead of using connectors outside of one: using small, standard grey IP65/IP66 boxes with their grommets/strain relief to connect the wires in a guaranteed splashproof and water jet-resistant environment. No idea if the boxes and their bits and pieces work out more costly than the type of connector you show or things like MC4. Upside, no jet sprays should get anywhere near the actual electrical connections.

What about MC4 or other outdoor photovoltaic connectors? I just looked on RS UK and they're (basically) about 2 to 3 GBP each - works out the same as the three-wire one you show the link to. Those have been used for years and look clunky but must be reliably waterproof. MC3 connectors should be cheap but it seems they are obsolete.

Are the variously-shaped gel-filled connectors at least IP65 if not quite IP66? They must be because I see them all over the place in outdoor jobs.

In principle, I would guess there's nothing wrong with the connector you are worried about - only the unflattering photo and the sloppy lack of a datasheet/tech specs drawing sheet. It looks to me like any old mass-produced plastic thing for industrial purposes: Not designed for aesthetic appeal, just to work in a wet environment. The two customer reviews I read seem okay, if they are real comments. It looks fine to me. Get a sample one - that's the only way to be sure, but it looks fine.
 

Hi,

... a specification about pin count and current rating?
Do they need to be waterproof in connected state only .... or also in unconnected state?
With or without mechanical lock?
Single litz or cable?

Klaus
 

.. a specification about pin count and current rating?
Do they need to be waterproof in connected state only .... or also in unconnected state?
With or without mechanical lock?
Single litz or cable?
Thanks, LED lamps draw about 0.5A or less.
The connectors will only need be waterproof when connected
Prefer mechanical lock, but if cheap will consider without
Sometimes it'll be 2 Amp rated mains cable, sometimes jutr some wire like 7/0.1 wire with go and return.
 

MC4 will certainly do the job, I have some here that have been carrying several amps at >250V DC for several years while exposed to the elements, including the heavy rain my area is famous for. They are quite bulky though.

Consider these which I also use:
https://www.digikey.co.uk/en/product-highlight/t/te-connectivity-amp/amp-superseal-ip67-connectors

They are two pin and completely watertight. The yellow sleeve is flexible and compresses into the other half to make a seal. There are also small individual seals that the wires pass through then push into the backs of the connectors to make the entry points watertight too. Tyco make them with more contacts as well if needed.

Brian.
 

Thanks, these are all great ideas. We are also thinking of cheaply "jacking" it, and using any old non waterproof connector, and shoving a small thin plastic "tube" over it when connected. and then having kind of jubilee clips pull tight at each cable entry end of the connector, so as to pull the plastic so it seals around the cable and connector, giving an element of waterproof-ness

Being super-cheap, we are even thinking of a bit of choc block, wire into each screw clamp, tie a knot in the wires as they go into the choc block, then a small plastic bag around this, then elastic band or jubilee-clip round this for water proofing.
 
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Thanks, these are all great ideas. We are also thinking of cheaply "jacking" it, and using any old non waterproof connector, and shoving a small thin plastic "tube" over it when connected. and then having kind of jubilee clips pull tight at each cable entry end of the connector, so as to pull the plastic so it seals around the cable and connector, giving an element of waterproof-ness

Being super-cheap, we are even thinking of a bit of choc block, wire into each screw clamp, tie a knot in the wires as they go into the choc block, then a small plastic bag around this, then elastic band or jubilee-clip round this for water proofing.

Not saying the plastic bag wouldn't work but you might have condensation problems.
 

I wonder just how conductive cleaning water is going to be?
I mean, the most conductive type of water is sea water, and that has a Rho of 0.2.
Therefore, a rectangle of water of length 1cm and area 1mm^2 would have a resistance of 2kOhms.
So its not even very conductive…..i don’t see short circuiting being a great problem. I wonder why there are so many waterproof connectors.
 

I wonder just how conductive cleaning water is going to be?
I mean, the most conductive type of water is sea water, and that has a Rho of 0.2.
Therefore, a rectangle of water of length 1cm and area 1mm^2 would have a resistance of 2kOhms.
So its not even very conductive…..i don’t see short circuiting being a great problem. I wonder why there are so many waterproof connectors.

Not and expert but I think the main problem is corrosion with DC voltage.
 

I recently had to investigate the failure of a water sterilization unit. Although it processes large volumes of water, the actual UV reactor unit holds an open ended quartz flask (a giant test tube) with a mercury vapor tube in it which is open to the atmosphere. The tube is basically the same as a standard fluorescent tube but has no internal paint coating. Like an ordinary tube, it has a heater electrode at each end and in this model, an electronic ballast with PFC input. The failure was that wires to one end of the tube had completely dissolved into about 1cc of water condensate. It demonstrates very effectively how even a small current can cause serious corrosion. Consider that the condensate was essentially distilled water from the atmosphere and the only possible current path was capacitive through the quartz flask wall and then about 20mm of 'fresh' water to ground through the pipework. Even the output of the ballast was floating from the secondary of a ferrite transformer. I would guess the total capacitance the current flowed through was probably no more than about 20pF but it completely corroded away 1mm wires.

Keep it watertight Treez, avoid all water contact, even condensation in plastic bag.

Brian.
 

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