Taking power to the shed

[Monkeh]

And what provision have you made for rising sea temperatures causing flooding, or possible terrorist attacks, or the yellowstone park supervolcano going off, or the astroid striking the earth. Come on op - own up. You've made no preparation at all

It's not reasonable to make provision against those, particularly the ones that will end civilisation as we know it, and it does distract from the genuinely important things.

Sex, drugs, and rock 'n roll?

 

[fridgefreezer]

Could I just extend the ring main and the lighting from the house to the garage instead, and do away with the consumer unit in the shed?

 

[RF Lighting]

NO! You need to run the circuit's in SWA, and extend your equipotential zone by bonding all extraneous metal work with at least a 10.0mm² conductor

The more you ask the more and more I get the feeling you are out of your depth with this job and you really ought to employ an electrician to do it for you.

 

[fridgefreezer]

ok, that's fine. I appreciate a straight reply rather than the other silly attempts at the same thing, but falling flat.

I'm more than willing to listen to good advice, but not little boy's games.

Cheers chaps.

 

[ban-all-sheds]

Hi there. Ok, following on from my post about the SWA abbreviation, here's the project that gives rise to that question.

In short, I want to connect this

View media item 26911
To this:

View media item 26912 View media item 26913
I am planning on using 6mm 3c SWA.

How do you propose to gland the SWA into the house CU?

Only put there because it was spare from an earlier project, and I didn't want to buy another. I can see now that the one in the photo would be inadequate.

The CU is OK, it's supplying it from an RCD in the house that's dodgy.

None. I took advice from a cable supplier based on the demands I expect to have.

You have to take responsibility for the design, not the cable manufacturer.

• http://www.tlc-direct.co.uk/Book/6.1.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/6.2.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html[/list]
  
  
  

  What provisions will you be putting in place to minimise distruption from your shed electrics tripping out an rcd in your house can causing you inconvenience?

  ***I don't know***

  Don't supply it from the house CU is the answer.
  
  
  

  What type of supply do you have?

  ***Don't know***

  You need to know, as it affects the rest of your design.
  
  //www.diynot.com/wiki/electrics:earthing-arrangements
  
  //www.diynot.com/wiki/electrics:earthing-supply-types-and-bonding
  
  
  

  Are there any exposed extraneous conductive parts in the shed?

  ***Yes, see above***

  Read this.
  
  
  

  How much is LABC notification in your area?

  ***Don't know***

  Are you aware of Part P ?

  ***Yes***

  Even if you don't intend to notify, what are you going to do about testing?
  
  
  PS - wasn't it a lot harder to keep typing all those asterisks than simply highlighting a block of text and clicking the Quote button?

 

[ban-all-sheds]

I'm more than willing to listen to good advice.

You need an electrician.

The thing is, designing circuits, installing new CUs, outside supplies, submains etc, and then testing them to confirm they are safe, is not a trivial job, and I can assure you that it involves knowing far more than you think it does.

Asking questions here can be a useful part of a learning process, but they are not a substitute for proper structured studying. The key term there is "learning process" - you cannot learn all the things you need to know just by asking questions here. It isn't structured enough - it won't provide you with a way to progress where each step builds on what you learned before.

You can't carry out a job of this magnitude by asking whatever random questions happen to occur to you. You've already shown that you have some dodgy misconceptions - what if you get something wrong because you have no idea your knowledge is wrong? What if you miss something because you simply have no idea it even exists, and just don't realise you don't know it?

 

[fridgefreezer]

Couldn't agree more.

I'll post a bit more when I've read the bed time story.

 

[ban-all-sheds]

If you want a tester, you could do worse than this:

http://cgi.ebay.co.uk/Unitest-Telar..._Measurement_Equipment_ET&hash=item336177c58c

Out of calibration, but looks in good condition.

Don't pay full price - no more than £150 all in. Offer him £120 and see what he says.

 

[swingles]

Op, as rude and unpleasant as some of the posters on here come across as, if you're not sure then get an electrician in. Other than that, read between the lines, look for techniques on youtube and ask normal human being professionals for advice instead of those that hide behind reality on here.

 

[fridgefreezer]

I'll try to deal with these points in reverse - as they appear on the screen below.

@ Swingles
I don't get fazed by the curious 'comments', either on this forum or any other - I'm here to get specific information, not have an argument.

You're dead right - I don't want to be dead, nor anyone else who comes near my house; I'm happy to have a qualified tradesman here, be it lecky or plumber or carpenter etc. My reason for having this interest now merely stems from my own 'tinkering', for want of a better word, with lecky circuits many years ago, and perhaps I thought too much of my abilities then, and thought they might be useful now. Hey! I'm probably wrong, but it was worth a try.

And I think I will hunt around a bit before finally giving in to the reality that I could spend less time on this thing by getting a pro-lecky guy in.

Right,
@ban-all-sheds
Yes, as I said earlier, I think you are correct there. I can't add much, but further to your previous post...

I thought I had a grip on connecting the SWA/gland to the metal CU, but agree that I had not given any thought to earthing the gland to the house CU - it is plastic, afterall.

Yes, I was happy with the CU with the three ways in it, but I had not appreciated until today that that would really only be good for two circuits and only one lighting circuit. Now I know I need a larger/more capable one. Thanks.

I don't really understand what you are saying when you say this:

[/quote]Don't supply it from the house CU is the answer.

, in response to when I say at one point that I do not know what provisions will I be putting in place to minimise disruption from my shed electrics tripping out an rcd in the house?

How else could I supply the shed?

I won't go into the other points now, not because they're not important, just that I take on board your opinion. They matter!

***As for the asterisks...*** - I didn't know then how the tags worked. I do now.

@RF
Ok, noted about earthing.

But this line clinches it, I think:

Then you need an electrician to split your meter tails and provide you with a non-RCD protected 50A metalclad switchfuse at your mains position to connect the SWA to.

! Many thanks.

 

[electronicsuk]

I don't really understand what you are saying when you say this:

Don't supply it from the house CU is the answer.

, in response to when I say at one point that I do not know what provisions will I be putting in place to minimise disruption from my shed electrics tripping out an rcd in the house?

How else could I supply the shed?

[snip]

But this line clinches it, I think:

Then you need an electrician to split your meter tails and provide you with a non-RCD protected 50A metalclad switchfuse at your mains position to connect the SWA to.

! Many thanks.

You answered your own question!

 

[fridgefreezer]

Ah, yes, I see. Cheers.

'Splitting tails' - isn't that potentially quite dangerous?

 

[Monkeh]

Ah, yes, I see. Cheers.

'Splitting tails' - isn't that potentially quite dangerous?

Only if you do it live like a fool.

 

[electronicsuk]

Ah, yes, I see. Cheers.

'Splitting tails' - isn't that potentially quite dangerous?

I think you may be confusing it with spitting nails, which can in fact cause serious damage to your mouth and tongue!

As long as the work isn't done live, the tails are split properly using a henley block and fused down/protected appropriately, it's absolutely fine. It's often used as a method to install electric showers where there are no spare ways in a CU or the existing installation would otherwise require upgrades that the customer isn't willing to pay for, so it's quite normal practice.

 

[ban-all-sheds]

I thought I had a grip on connecting the SWA/gland to the metal CU, but agree that I had not given any thought to earthing the gland to the house CU - it is plastic, afterall.

Plastic isn't an issue electrically - you'd have a banjo or earthing nut for the gland, but space inside the CU and mechanical strength of the plastic case would be.

Yes, I was happy with the CU with the three ways in it, but I had not appreciated until today that that would really only be good for two circuits and only one lighting circuit.

No - it's good for a total of two final circuits. Count the spaces in the cover and the number of prongs on the bus-bar.

Now I know I need a larger/more capable one.

How big is the shed?

I don't really understand what you are saying when you say this:

Don't supply it from the house CU is the answer.

,
in response to when I say at one point that I do not know what provisions will I be putting in place to minimise disruption from my shed electrics tripping out an rcd in the house?

How else could I supply the shed?

Don't supply the shed from the house CU.

Take the meter tails into a service connector block

Then to to existing house CU and to a switchfuse supplying the armoured cable to the shed.

Isolating the supply to make this a safe thing to do is a bit of a snag though....