Underwater Splice

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MNSparky

MNSparky

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Location
Minneapolis, MN
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Electrical Contractor - 2023 NEC
So what's your favorite splice kit for use underwater?

I service a condo building that has an in-ground, open bottom splice box for their parking lot poles that some ignoramus put at the bottom of a hill, just inside the curb and gutter. Every spring for the last 3 springs this box has filled completely to the top with water as it is at the low point for all the snow melt and the curb acts as a dam. Last year I dug it out and backfilled coarse gravel encased in landscape fabric under it 2' deep. I replaced the "watertight" wirenuts I used the first year (that didn't work) with grease tubes and figured it would be good to go. Nope, was just there and the box is full of water and the breaker is tripped. :rant: So, barring any major drain tile work, any ideas? I need a connector I can get six #10s in that will last being underwater for maybe a couple months every year. I haven't done a lot of underwater work so I'm open to ideas.... Thanks!
 
MNSparky said:
So what's your favorite splice kit for use underwater?

I service a condo building that has an in-ground, open bottom splice box for their parking lot poles that some ignoramus put at the bottom of a hill, just inside the curb and gutter. Every spring for the last 3 springs this box has filled completely to the top with water as it is at the low point for all the snow melt and the curb acts as a dam. Last year I dug it out and backfilled coarse gravel encased in landscape fabric under it 2' deep. I replaced the "watertight" wirenuts I used the first year (that didn't work) with grease tubes and figured it would be good to go. Nope, was just there and the box is full of water and the breaker is tripped. :rant: So, barring any major drain tile work, any ideas? I need a connector I can get six #10s in that will last being underwater for maybe a couple months every year. I haven't done a lot of underwater work so I'm open to ideas.... Thanks!
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You're probably not going to want to spend the ~$1100 for it, but the principle is essentially a 'diving bell' where you bring your connections into the ground box and don't have to worry about the submersible connection (https://www.legrand.us/markets-solutions/outdoor/ground-box.aspx). We've used these on a project recently and haven't had any issues with them, but the $$ may not be worth it to you or your Condo building.

The other option is using an above ground splice box similar to what the utility uses for their secondary boxes serving houses.

Did I read correctly though that is is in an area that cars can drive over inside the curb area? If so, my previous two suggestions may not work at all.

Edit** --- This connection is used frequently by the local municipality for their street lighting circuits that have pull boxes that gather water as well and seem to work: http://www.nsi-sales.com/iplw_itw_series.htm (Polaris Blue submersible connectors/reducers/taps)
 
tw1156 said:
You're probably not going to want to spend the ~$1100 for it, but the principle is essentially a 'diving bell' where you bring your connections into the ground box and don't have to worry about the submersible connection (https://www.legrand.us/markets-solutions/outdoor/ground-box.aspx). We've used these on a project recently and haven't had any issues with them, but the $$ may not be worth it to you or your Condo building.

The other option is using an above ground splice box similar to what the utility uses for their secondary boxes serving houses.

Did I read correctly though that is is in an area that cars can drive over inside the curb area? If so, my previous two suggestions may not work at all.

Edit** --- This connection is used frequently by the local municipality for their street lighting circuits that have pull boxes that gather water as well and seem to work: http://www.nsi-sales.com/iplw_itw_series.htm (Polaris Blue submersible connectors/reducers/taps)
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Nope it's in the grass, just inside the curb from the parking lot. I thought about the pedestal style above ground box, but that's my last resort. I'd have to extend all the piping coming into the box up about 2' and then repull all the wire going out to the poles as it would then be too short. I'm fine with all that but the condo people don't want a pedestal sticking out of the ground. If these next splices don't work, that's the direction I'd go.
 
MNSparky said:
So what's your favorite splice kit for use underwater?

I service a condo building that has an in-ground, open bottom splice box for their parking lot poles that some ignoramus put at the bottom of a hill, just inside the curb and gutter. Every spring for the last 3 springs this box has filled completely to the top with water as it is at the low point for all the snow melt and the curb acts as a dam. Last year I dug it out and backfilled coarse gravel encased in landscape fabric under it 2' deep. I replaced the "watertight" wirenuts I used the first year (that didn't work) with grease tubes and figured it would be good to go. Nope, was just there and the box is full of water and the breaker is tripped. :rant: So, barring any major drain tile work, any ideas? I need a connector I can get six #10s in that will last being underwater for maybe a couple months every year. I haven't done a lot of underwater work so I'm open to ideas.... Thanks!
Click to expand...

I always liked these in this kind of a situation: [FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Scotchcast-Connector-Sealing-Pack-3570G-N/?N=5002385+3294253196&rt=rud
[/FONT]
 
texie said:
I always liked these in this kind of a situation: https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Scotchcast-Connector-Sealing-Pack-3570G-N/?N=5002385+3294253196&rt=rud
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Hey, I like that. That might just work. How many big blue wire nuts can you do with a kit?
 
We had a similar problem a couple of years ago. We put a small non-metallic j-box inside the pit box, took the conductors into that, made the slices, and filled it with a 3M 2123C re-enterable potting compound. Good to go.
 
If you can get to the individual #10’s seal them individually. For submersible well pumps, I buy a waterproof splice kit from my pump distributor. A #10 kit for 4 wires costs 2-3 dollars. Includes the butt splices and individual precut heat shrinks. I stock them for up to #2 wire. Bigger than that, I buy the Butt splices and 3 ft lengths of heat shrink from my electrical supplier.
 
I have done numerous submersible motor splices, using 33 and Scotch Cote, or heavy wall heat shrink with sealer. All are 150+ feet under water. Heat shrink may not work for smaller wires.
Have also done a lot of splices using "splice tanks" or 3M scotch cast kits, a 6" long clear plastic tube, make the splice, snap the plastic body aroud the splices, tape the ends, mix the two part fill and pour. Very reliable but can not get back in.

I like this solution
"We had a similar problem a couple of years ago. We put a small non-metallic j-box inside the pit box, took the conductors into that, made the slices, and filled it with a 3M 2123C re-enterable potting compound. Good to go."

I have done some instruments with re-enterable compound, yes you can get back it, but its sticky gooey stuff to pull out.
 
We use these to make splices on the tank gauge cabling for UST's.

Squeeze one side of the bag and the inside divider breaks open to allow you to mix the product. Once mixed, cut off one end and put the wirenut into the pack and use a wire tie to close off the bag. Leave open end up while it dries.

You don't get back into it afterwards. I don't know if it will work for 6 #10's, but I think a wire nut that takes 4 #10's would fit.

https://www.amazon.com/3M-3570G-N-Connector-Sealing-Pack/dp/B01IRPQ4AE
 
oldsparky52 said:
I've put more wire under a nut than listed so ... I'm not casting aspersions, but ... if I'm reading the data sheet correctly, that is only rated for four #10's. The reason I asked you is that I don't recalls seeing a wire nut that is rated for 6 #10's and I was curious.
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Perhaps I'm reading the "wire matrix" table wrong... There's a dot where the combination of three #10 str and three #10 str intersect so I take that as I can put six #10 str in it. Am I wrong?
 
Install a sump pump, tapping into the existing circuits. To disguise the discharge, make it look like a decorative fountain. It may run continuously for 3 months or so. Of course, then someone will complain that the fountain only works when it rains. :roll:
 
MNSparky said:
Perhaps I'm reading the "wire matrix" table wrong... There's a dot where the combination of three #10 str and three #10 str intersect so I take that as I can put six #10 str in it. Am I wrong?
Click to expand...

I've looked at that "wire matrix" but I do not understand how to correctly read it so I can't say yes or no to the way you read it.

I do however notice that the mm squared section (a little above that table) says 2-5 4mm sq may be put together and only 2-4 of the 6mm sq conductors may be put together. A # 10 is 5.621 mm sq so I have my doubts that this is listed for 6 #10's since the number of conductors is limited to 5 in a smaller wire size (the 4mm sq size).

Maybe some who knows can chime in and clear this up.
 
Around here Wa State Seattle--The poco uses the polaris style taps--we are tryiing them in a few locations--Seem to work fine--even submerged
 
oldsparky52 said:
I've looked at that "wire matrix" but I do not understand how to correctly read it so I can't say yes or no to the way you read it.

I do however notice that the mm squared section (a little above that table) says 2-5 4mm sq may be put together and only 2-4 of the 6mm sq conductors may be put together. A # 10 is 5.621 mm sq so I have my doubts that this is listed for 6 #10's since the number of conductors is limited to 5 in a smaller wire size (the 4mm sq size).

Maybe some who knows can chime in and clear this up.
Click to expand...

I see what you're talking about. I have an email into my 3M rep to clear it up, I'll post it when I hear back.
 
I have an answer! The sizing matrix confused many at my supply house and at 3M, but I finally got clarification on it from their tech support.

The matrix is indeed additive, you have to take the quantity of one size on the vertical column and the quantity of the other size on the horizontal column. If there is a dot where they intersect, you are good to go. In my example, I want to splice 3 #10 str with 3 more #10 str. There is a dot where they intersect so I can put six #10 str in that connector.

I told them it would be nice to include some instructions on how to read the table...:slaphead:
 
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