Ducting reducer or not bother?

[catdog1121]

Could do with bit of advice, running a 6mm SWA from consumer unit to shed, where I exit the house will be through the slab foundations straight underground. To do this ill need a long SDS drill bit.

My issue is I would like to use twin walled 40mm underground ducting however I cannot make a 40mm plus hole to get it into the building, obviously I dont want to end it early cause it will fill with water, been trying to find some kind of coupler to attach rigid 25mm conduit that I can get through the hole in the foundations to the 40mm underground ducting but cant find anything.

Anybody know of anything or should I just not bother with the ducting and lay the SWA without ducting, the ducting was only going to be used for extra protection, is this overkill and not worth the hassle?

 

[Charlie_]

40mm core drill?

 

[catdog1121]

40mm core drill?

Problem is the hole through the foundations needs to be drilled though the cavity so needs to be done at an angle with a meter long SDS drill bit, There is just no way ill get a core drill to drill the hole.. Im thinking maybe a wiskabox underground connecting the two, no terminations but use it like a straight through conduit box.

 

[Charlie_]

You wouldn’t get a job in Hatton Garden with that attitude..

Could you drill a few holes with your 25mm bit to make one big 40 ish mm hole?

 

[ruston]

A waterproof manhole get you in?

 

[ruston]

A waterproof manhole get you in?

 

[Charlie_]

A waterproof manhole get you in?