Waterproofing electrical connection

I have a drainage pump in a manhole which connects to armoured cable in a box at the top (inside) the manhole. All is well until the pump breaks down, water level rises and the box does not keep the water out. Local electric store says they have nothing to help so I wondered ..... can I literally fill the box with silicon to solve the problem. At the outset the connection should have been made above ground ( a wall about 8 feet away) but alas, there is now not sufficient cable to play with meaning the connection has to remain inside the manhole. Any help appreciated.

Peter

Reply to
Peter
Loading thread data ...

These are listed by Screwfix

formatting link

Reply to
Andy Cap

looking at the price of pumps, the cost of wp boxes and the inconvenience of having perhaps a compound filled box in the manhole, maybe a new pump is the best option. How have you solved the breakdowns you report?

Jim A

Reply to
Jim Alexander

I recently pulled out the pump (after a breakdown) and put a socket on the wire to test it. It failed. On a whim I cut the wire shorter and found that it worked fine. Then used it to lower the water level until I could reconnet it back in the manhole. Since water had not only entered the box and tripped the electrics but also (apparently) seeped into some few feet of the pump cable, I am quite keen for a waterproof solution. I need to connect armoured cable to normal 3 core (somewhat thinner) cable. Would silicon work?

Peter>

>
Reply to
Peter

Would any of these connect differing thicknesses of cable?

Thanks

Peter

Reply to
Peter

What about 'Self-amalgamating tape' ? It's a rubbery tape, in order to use it you remove the backing material and stretch it. You then use it to 'over-wrap' whatever you're waterproofing, bandage-style.

It then sticks to itself, forming a kind of rubber sheath over the cabling. Being a tape, it will cope with cables of different diameter

- and it can be 'stanley-knifed' off if you ever need to remove it.

Avaliable from CPC, Screwfix etc...

I used one of the 'waterproof' junction boxes from Screwfix in a damp location (to do with a pump in a septic tank system - but the box was well above the water level), and it was pretty useless ! Self-amalgamating tape was much more effective.

Hope this helps Adrian

Reply to
Adrian

Good point. Forgot about the armoured bit ! Need someone who's conversant with the box spec and size of armoured cable I guess.

Andy

Reply to
Andy Cap

Is it impossible to replace the flex on the pump?

Reply to
dennis

There is a special (heat sealed?) connection at the pump (rather like the sealed 3 pin plugs). I think that would be a 'send back to the manufacturer jobbie'

Peter

Reply to
Peter

if you want to retain your existing pump and its (probably) not practicable to rewire the pump I would extend the pump cable with similar diameter flex. Much easier to wp that than different cable types and diameters. Move the armoured cable to where you really want it.

Don't have a link to hand but I've used compound filled boxes to do this. Alternatively, individually heat shrink sleeve and overall self amalgamating tape as suggested.

Jim A

Reply to
Jim Alexander

This sort of thing...

formatting link
perhaps and really designed for SWA both sides but definately waterproof.

Jim A

Reply to
Jim Alexander

This is what I would look to use (or something like it). In my experience silicon sealant / self amalgamating tape will not work when you are dealing with submersion. As you have found, water will quite happily wick up a length of cable.

Chris

Reply to
Chris

Many thanks to all

Peter

Reply to
Peter

Well, it would certainly be possible to make up one using appropriate sized cable glands and a gaskit sealed box. Note that I don't believe even the CW SWA glands are submersible, so you will probably have to use regular (non-SWA) glands to seal against the outer sheath at the box, and then use a standard BW SWA inside the box to make a good connection to the armour (if necessary). The regular glands will either need sealing washers against the box, or use a sealant on the mating surfaces. The box, being unvented, will form condensation, so make sure you have large crepage distances between the connections.

Another option would be a submersible connector (B&Q had some going cheap a couple of months back, which may mean they no longer stock them) to join to a similar short length of rubber cable, and a potted joint connecting that to the SWA. I don't know what life you might expect from the submersible connector.

Reply to
Andrew Gabriel

Peter said the following on 11/05/2007 07:47:

Silicone might work, but you would be better of with epoxy potting compound. Cheapest place around is Maplin (mail order only - they never have it in-store)

formatting link
is the supplier spec.

formatting link
that you will only need to buy the 250g pack to fill a small junction box.

HTH

Reply to
Rumble

Cheers for that, I think thats the way I'll go.

Peter

Reply to
Peter

No, that would be IP68 (complete immersion) IP67 is protected against immersion for a specified time and depth (

Reply to
JohnW

Reply to
The Wanderer

Maplin sold IP68 mains connectors at one time - I have one submersed in my pond for the pump. Don't know whether they do them now or not. Made by Bulgin IIRC. That would be the best way to extend the flex I reckon.

Rob

Reply to
robgraham

Would that the man who wired the cesspit pump in my house were so wise. The house stood empty for several months before we moved in, so they switched off the electricity. The ground water seeped into the septic system and filled the overflow tank, above the connector for the pump, which wasn't IP-anything, much less submersible. We moved in, switched on the 'leccy, pop! Silence. Darkness. Fortunately it was daylight and some experimentation found the problem. The removals men were then treated to the sight of me bailing out the tank with a bucket on a rope in order to reach the connector. Of course, water had wicked down the cables in both directions and ruined them. Fortunately, the spare pump lead had been coiled up under the manhole cover, cutting off a couple of metres sorted that. But for a couple of weeks after moving in, we had an extension trailing across the garden to power the pump.

Reply to
Huge

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.