Would you run a sub-main..

[screech]

The unit we are working at, has a 3phase proteus (yuk!) DB at the front of the unit.

The unit is approx 33mtrs long by approx20mtrs wide.

The guy who has asked me to help him out on the job has agreed to run power lights etc circuits to various areas.

Now the sockets they have marked out are more than halfway down the unit, as it will be the warehouse area and the front is going to be build up to a shop/showroom.
Iv just been there for a measure up, and the first socket is 35mtrs away from the main DB, then goes on for another 10mtrs or so to the last one (on that area/circuit)
Plus i expect they will want rear door access srur, fork lift charging point, other lighting circuits etc.

This all seems to be planned to be run very long runs from the main DB!

Im thinking of putting another plan forward to them, run a 16mm sub main to a single phase DB Near the other end, more cental to all the circuits that will be at that end of the unit.

This will run, max, one ring, 2 lighting 2 spurs and a forklift charging point.


What would you guys do, run the long runs as 'planned' or do it more like my way???


cheers

 

[bugsy]

Depends on the number of circuits to be run the the other end - which will be more cost effective

 

[screech]

Cost wise, i dont think the guy is really too bothered, for the price of 40mtrs(max) of some 16mm and a single phase board. I think will be saved on the cost of cable that would be used on the extra long runs.

One ring @ just over 100mtrs, or probably 40mtrs if done my way.
Two door access spur circuits @ 45 - 50mtrs or 20mtrs max my way.....
Forklift charger, 40mtrs of 4mm or 5mtrs of 4mm... soon adds up?

Plus obviously... after the initial half day for installing the submain... time saved pulling all the way down the unit countless times.

Hmm... i think iv answered my own questions...


cheers

 

[bugsy]

Cost wise, i dont think the guy is really too bothered, for the price of 40mtrs(max) of some 16mm and a single phase board. I think will be saved on the cost of cable that would be used on the extra long runs.

One ring @ just over 100mtrs, or probably 40mtrs if done my way.
Two door access spur circuits @ 45 - 50mtrs or 20mtrs max my way.....
Forklift charger, 40mtrs of 4mm or 5mtrs of 4mm... soon adds up?

Plus obviously... after the initial half day for installing the submain... time saved pulling all the way down the unit countless times.

Hmm... i think iv answered my own questions...


cheers

Becomes a lot clearer when looking at it from another prospective

 

[chris gray]

we had a similar situation just before christmas, we got called in to help a company out. he'd already priced the job and bought the materials.
we spent a day and a half mounting uni-stut and running 60-70mtrs of 9" tray, when a sub-mains would of taken not that long and been a world cheaper.
the 7 p's

 

[screech]

cheers guys

now to get some prices! And work out what cable to use... t+e, swa or hi tuf!


cheers

Guys,
just been thinking about this cable today, and as the all the other cables above the ceiling (1200x600 suspended tiles) will be t+e, i cant find a reason why my sub-main cant be a 16mm t+e, and run a sparate 6 - 10mm earth with it....

what do you think?

cheers

 

[Bobby B]

SWA all the way

 

[gaffer]

16mm 3 core SWA,sorted.

 

[peteludman]

how many amps on a 16mm swa.
just dont forget about volt drop mate.or dose it have a private supply

 

[screech]

It wouldn't of had much load on it, was going to back it up on a 50a breaker.

Doesn't look like I'm going to do it now. Going to stick with the long runs!!

I'm just concerned about the length of the ring, I can't remember what the mac length a 2.5mm ring can be. I reakon it's going to be about 110mtrs (there and back) no more than that.


Cheers

It wouldn't of had much load on it, was going to back it up on a 50a breaker.

Doesn't look like I'm going to do it now. Going to stick with the long runs!!

I'm just concerned about the length of the ring, I can't remember what the mac length a 2.5mm ring can be. I reakon it's going to be about 110mtrs (there and back) no more than that.


Cheers

 

[pennywise]

Would definately have the showroom area and the rear warhouse on two seperate DB's.

 

[bramboy]

Recently had similar issue on a job, slightly larger 3 phase merlin gerin 12way fully loaded £1100.Bloody Rcbos!

 

[peteludman]

I think that's to long for a ring I think max is abot 40 m out and 40 back so about 80m well 88meters to be more procise so I would use 4mm I know I keep on but VD watch out mate .
I know its not taking much power at moment but you can take more in the future sub main would be better