What size ducting for services?

[gwebstech]

Hi all

 

What sizes are the water pipe that will come into the house for a new build connection? i need to knwo what size ducting to buy to route the water and electricity cables through thr concrete floor.

 

Is it just the elec and water that needs the ducting?

 

thanks

[Declan52]

 

You need to do a list of everything in your house that will need to have a duct. Showers, baths, toliets,sinks, washing machines all need to get rid of water and other stuff!!! Then you have your electric,bt,gas, heating pipes, power to outside gates or shed etc.

 

You use these for the water bits.

https://www.screwfix.com/p/floplast-long-radius-bend-87-5-110mm/81100

Everything then gets put inside these or connected to them. Water, waste water ,  toilets etc. The blue water pipe will just be pushed up the inside.

For electric it will need to come via a black duct . It will depend where you meter box is going so might need one of these if it's a cavity build.

https://www.meterboxesdirect.co.uk/electric-meter-box/meter-box-hockey-sticks.html

Telephone cables will be via a grey duct like these

https://www.draindepot.co.uk/plastic-underground-ducting/bt-ducting.html

I have seen telecoms put in everything from sewer pipes to the proper grey ducting though. Only thing is make sure you put in some draw rope to pull the cable from the out side into where ever you want the cable to go to. Same goes with the electric cable duct. It's up to you to get the ducting from your house to the edge of the site to the location of the water main, bt box etc so make sure you put draw rope in the ducts. 

And this is very very very important measure and measure and then get some one else to measure and check each and every position of every duct before you pour any concrete. Will be a few mins to move a duct then. After the concrete is in its a major pain in the arse.

 

 

 

[jamieled]

Would there be any major downsides to just burying a 25/32mm MDPE water pipe and have it come up through the foundation, rather than have it coming through a 110mm duct? Asking out of interest as I'm at a similar stage.

[Russell griffiths]

8 hours ago, jamieled said:

Would there be any major downsides to just burying a 25/32mm MDPE water pipe and have it come up through the foundation, rather than have it coming through a 110mm duct? Asking out of interest as I'm at a similar stage.

You shouldn’t have it coming straight through a foundation, needs a duct to prevent damage and different movement in materials, but it doesn’t need to be 110mm. 

32mm pipe in a 50-60mm duct or 25mm pipe in some 45mm duct. No need for 110mm. 

[Jeremy Harris]

Most of our stuff comes up through the slab in ~50mm ducting, except for the power cable.  That's a length of 25mm² 3 core SWA, and is in 100mm ducting just to make it easier to pull in.

[PeterW]

5 minutes ago, JSHarris said:

Most of our stuff comes up through the slab in ~50mm ducting, except for the power cable.  That's a length of 25mm² 3 core SWA, and is in 100mm ducting just to make it easier to pull in.

 

I can concur with that ..! We used a 63mm duct for electric and the 25mm cable was an utter cow to pull through and caused no end of issues at the house end. 

[Oz07]

Wont water board have some say on size of duct for water pipe. I know customer self installs that end but usually here they are pretty strict.

[Hobbiniho]

up here BT supply ducts if you ask nicely and 25mm water pipe fits in them nicely 

[Onoff]

Read your utilities companies guidance on this if possible. Some electricity companies insist on red duct at whatever voltage.

 

Some general guidance:

 

http://www.pavingexpert.com/ducting.htm

 

https://www.jdpipes.co.uk/knowledge/ducting/ducting-different-colours.html

 

https://www.drainagesuperstore.co.uk/blog/underground-ducting-colour-codes-explained/

[recoveringbuilder]

On 04/06/2019 at 08:09, Oz07 said:

Wont water board have some say on size of duct for water pipe. I know customer self installs that end but usually here they are pretty strict.

We originally put our water pipe through a random duct but when Scottish water came out to inspect they wouldn’t accept it and we had to change to the blue duct specifically for water pipe, bt supplied their duct and a roll of rope to draw through and SP energy supplied red duct for the cables .

[gwebstech]

On 03/06/2019 at 21:46, Declan52 said:

 

You need to do a list of everything in your house that will need to have a duct. Showers, baths, toliets,sinks, washing machines all need to get rid of water and other stuff!!! Then you have your electric,bt,gas, heating pipes, power to outside gates or shed etc.

 

You use these for the water bits.

https://www.screwfix.com/p/floplast-long-radius-bend-87-5-110mm/81100

Everything then gets put inside these or connected to them. Water, waste water ,  toilets etc. The blue water pipe will just be pushed up the inside.

For electric it will need to come via a black duct . It will depend where you meter box is going so might need one of these if it's a cavity build.

https://www.meterboxesdirect.co.uk/electric-meter-box/meter-box-hockey-sticks.html

Telephone cables will be via a grey duct like these

https://www.draindepot.co.uk/plastic-underground-ducting/bt-ducting.html

I have seen telecoms put in everything from sewer pipes to the proper grey ducting though. Only thing is make sure you put in some draw rope to pull the cable from the out side into where ever you want the cable to go to. Same goes with the electric cable duct. It's up to you to get the ducting from your house to the edge of the site to the location of the water main, bt box etc so make sure you put draw rope in the ducts. 

And this is very very very important measure and measure and then get some one else to measure and check each and every position of every duct before you pour any concrete. Will be a few mins to move a duct then. After the concrete is in its a major pain in the arse.

 

 

 

 

Thanks for the bruilliant reply Declan, ill check those products out. I know the toilet waste has to be in situ,  the waste water ie from sinks will go in pipes coming out of the walls. as will the other 2 toilets will be coming out of the outside wall and down.  im assuming that the gas and elec they would go to the meter boxes  on the wall and were covered with a protective pipe like on my house (built circa 2001)

 

thanks

Edited June 5, 2019 by gwebstech

[gwebstech]

On 04/06/2019 at 07:53, JSHarris said:

Most of our stuff comes up through the slab in ~50mm ducting, except for the power cable.  That's a length of 25mm² 3 core SWA, and is in 100mm ducting just to make it easier to pull in.

 

Is this on a new build? why not just run it underground on the outside of the house and up to the meter box on the outide of the wall?

[gwebstech]

and when you guys have used ducting to get xyz in the house, what did you fill it in with? otherwise it wont pass an air tightness test surely

[Jeremy Harris]

10 minutes ago, gwebstech said:

and when you guys have used ducting to get xyz in the house, what did you fill it in with? otherwise it wont pass an air tightness test surely

 

The method I used was this:

 

Get a short length of galvanised fencing wire, some chicken wire mesh and a can of foam.

 

Screw the chicken wire up into a ball and thread and tie the fencing wire to it, so that there's a length of fencing wire poking out.

 

Push the ball into the duct around the cable/pipe, leaving the fencing wire coming out the top of the duct.

 

Tape the fencing wire to the cable/pipe so it's out of the way.

 

Squirt can foam deeply into the mesh so that it expands to fill the duct.

 

Leave the foam to cure and carefully trim around the top.

 

This forms a vermin-proof plug, that can be pulled out if need by in the future, using the fencing wire.

 

[Jeremy Harris]

30 minutes ago, gwebstech said:

 

Is this on a new build? why not just run it underground on the outside of the house and up to the meter box on the outide of the wall?

 

 

Two reasons.  We wanted the meter box in before the house was built, so we could use it for the site supply (saved paying twice for it).  Also, having a meter box embedded in the wall of the house would have been a massive thermal bridge, the very last thing we wanted.

 

By placing the meter box in a fence that now forms our mandated wheelie bin screen, we could have the temporary site supply hooked up to it, then just swap over so that the cable supplying the house connected up to it later. 

[redtop]

4 hours ago, JSHarris said:

 

 

Two reasons.  We wanted the meter box in before the house was built, so we could use it for the site supply (saved paying twice for it).  Also, having a meter box embedded in the wall of the house would have been a massive thermal bridge, the very last thing we wanted.

 

By placing the meter box in a fence that now forms our mandated wheelie bin screen, we could have the temporary site supply hooked up to it, then just swap over so that the cable supplying the house connected up to it later. 

how long was the run from the meter to the consumer unit? i know some sparky's get nervous if its more than a couple of metres but the rules seem a little vague

[Jeremy Harris]

11 minutes ago, redtop said:

how long was the run from the meter to the consumer unit? i know some sparky's get nervous if its more than a couple of metres but the rules seem a little vague

 

 

The regs stipulate that meter tails cannot exceed 3m, but there's an easy (and sensible) way around that.  Just run the tails to a fused DP isolator switch (like these: https://www.tlc-direct.co.uk/Main_Index/Distribution_and_Switchgear_Index/Switchfuse_SP_and_N/index.html ) and then run a length of 25mm² 3 core SWA from the switch into the house.  Our run of SWA is around 15m, but it could easily be longer if needed.

[PeterW]

1 hour ago, redtop said:

how long was the run from the meter to the consumer unit? i know some sparky's get nervous if its more than a couple of metres but the rules seem a little vague

 

I’ve done 28m with no issues and an isolator switch on either end. The one on the meter end has a fuse in, the one on the CU end was just an isolator as only protecting 400mm of tails. 

[redtop]

makes perfect sense, cheers

[gwebstech]

10 hours ago, JSHarris said:

 

The method I used was this:

 

Get a short length of galvanised fencing wire, some chicken wire mesh and a can of foam.

 

Screw the chicken wire up into a ball and thread and tie the fencing wire to it, so that there's a length of fencing wire poking out.

 

Push the ball into the duct around the cable/pipe, leaving the fencing wire coming out the top of the duct.

 

Tape the fencing wire to the cable/pipe so it's out of the way.

 

Squirt can foam deeply into the mesh so that it expands to fill the duct.

 

Leave the foam to cure and carefully trim around the top.

 

This forms a vermin-proof plug, that can be pulled out if need by in the future, using the fencing wire.

 

 

brilliant, i hear brillo pads work well too

[gwebstech]

10 hours ago, JSHarris said:

 

 

Two reasons.  We wanted the meter box in before the house was built, so we could use it for the site supply (saved paying twice for it).  Also, having a meter box embedded in the wall of the house would have been a massive thermal bridge, the very last thing we wanted.

 

By placing the meter box in a fence that now forms our mandated wheelie bin screen, we could have the temporary site supply hooked up to it, then just swap over so that the cable supplying the house connected up to it later. 

 

so, the gas. elec, water companies want all their pipes ducted from the road right up to/inside the house then?

[Jeremy Harris]

Just now, gwebstech said:

 

so, the gas. elec, water companies want all their pipes ducted from the road right up to/inside the house then?

 

 

No, not usually.  All they own is the run from the road to the meter or stopcock.  In our case we don't have gas or mains water, and have the electricity meter out in a box in the fence outside, as it's more convenient for the meter reader, it was a handy location for our temporary site supply during the build and it's also a handy location to run the fairly hefty cable to the car charge point.

[Jeremy Harris]

8 minutes ago, gwebstech said:

 

brilliant, i hear brillo pads work well too

 

The snag with ordinary wire wool is that it corrodes very quickly.  Stainless pan scourers would probably work OK.  We used loads of industrial/catering stainless pan scourers as insect screening behind our cladding.

[Dreadnaught]

4 minutes ago, JSHarris said:

We used loads of industrial/catering stainless pan scourers as insect screening behind our cladding.

 

Hadn't thought of that as a solution: ingenious. Any reason why metal mesh, stapled in place, wouldn't have worked?

[Jeremy Harris]

9 minutes ago, Dreadnaught said:

 

Hadn't thought of that as a solution: ingenious. Any reason why metal mesh, stapled in place, wouldn't have worked?

 

 

Fine mesh works fine, but the unravelled curly scourers were just the right thickness to fill the 25mm gap and just be sandwiched behind the cladding at the top and bottom.  Being stainless means they should last practically forever, too.