Online assistance for electrical trade people Login  |  Register  |   Forgot Password
Assistance for electrical trade people




Click here to send Ron a pdf document for publication on this Topic

Documents must be less than 200k in pdf format

Posted By Topic: Supplying a MEN from a DB

Apr 10 2013 16:36

Hi all. Just a querie late last year i run a 6.0mm submain to a garage using 2c+e cable, it is unlinked and have protected it via a 25amcb over 30mtr. Anyhow now the cust wants another 70mtr run to a little shed to run computers and a light, purhaps a heater. I have run a 1/16+ns. I will protect this via a 20a mcb, alowing 1.5 percent vd., so total from house is 4% in the sub mains. The sub ccts supplied from this little board very very short will alow 1%. Question, can i supply a men swbd from an unlinked db? Ive looked in the book of words, and have found that as long as i crimp the incoming and outgoing neutrals at the at the db board then i shouldnt have a problem??? Or am i better making both swbds a men board, which i can easy do but obversly its more work, i just wanted to know if i can do it provided i crimp borth neutrals together so its not relying on a terminal or bar back at the db. Cheers in advance!!! Craig.

The Don
Apr 10 2013 17:10

Craig :I would agree with your understanding of the rules for outbuildings , the Neutral conductor must be continious from the Main MEN board to the outbuilding , also don't forget that the earth at the outbuilding is considered a Main earth so under the current regs this requires an inspection :)


Apr 11 2013 17:02

From what i understand of the rules , we have 2 options in wiring "outbulidings".

We can use a twin and E , and have an unlinked switchboard.....OR

We can have a MEN board which case the building must qualify for being classafied as an outbuilding........IE the building MUST be seperated by land.

I have in the past always liked to supply MEN from a MEN , and DBs from MEN or another DB.

In this case i have had no option but to run the supply from the garage supply , which we in our wisdom supplied in 6mm 2c plus earth in conduit.

There was neaver any talk of talking power to any other remote buidling , ( lesson lent must future proof)

so this time i will be supplying a MEN from an UNLINKED switchboard , so long as i crimp both neutrals together , i shouldnt have a problem.

unless i have missed something???



Apr 11 2013 17:43

Just out of interest, how are you going to crimp the neutrals together and terminate on the neutral bar as well?

eg. 6mm + 16mm in a 25mm lug on to a stud?

Apr 11 2013 17:54

6+16 Screen into a 16 lug , and if they dont fit a small shear bolt , and a 6mm black tail to the stud?


Apr 12 2013 09:16

A "line tap"and some black sleeving is another option. Line taps are made in many sizes so getting one of the correct size should not be a problem. put as lug on the 16 mm2 screen and line tap the 6 mm2 cable on to the screen conductor.