Temporary power to the building from our existing supply.

[saveasteading]

Some electric supply advice required please.

 

We have a garage building with our permanent electrical supply already installed and complete. This will later have an armoured cable from it to the barn conversion which is 15m away.

 

We have normal sockets in the garage from which we run 240V machinery adjacent or of course through a 110V transformer.

 

We also have a  commercial (rented) site canteen (15m from garage and 10m from barn.) This is supplied by an armoured cable. From this they are taking a 110V supply into the main building using a 220V socket, a transformer then 10m looping cable to the building and up to 20m cables therein.

This has been working successfully in operating fairly substantial electric saws etc. we are doing lots of cutting of 6 x 2.

 

However we now have to run a lot of lighting as well. Our workers are saying that there isn't enough power for both.

They are asking us to take in  a temporary 240V supply.

 

Of course this is another significant cost, involving trenching or some overhead draping of an armoured cable, and an electrician yet again.

Easy to ask for but we have to watch costs and I don't like the expectation that they get whatever they want.

 

Is there any technical reason why we can't simply use an additional 110V cable from the canteen? or 2 or any number?

 

Alternatively we could take the 110V from the garage direct to the main building.

 

It seems obvious to me but perhaps there is something I don't understand.

 

AND if it is simply a matter of more yellow cables, then I have to explain subtly / technically why it is not cheapskate and is perfectly sound. They can be sensitive flowers about not getting whatever they ask for.

 

If it helps I can do a sketch.

 

 

 

 

 

 

 

Edited 6 hours ago by saveasteading

[ProDave]

Better to use a heavy duty 240V extension lead and move the 110V transformer.

 

110V means a little more than twice the current so double the volt drop and larger cable needed.

[markc]

+1 keep 110v runs as short as possible. 2.5mm or even 4mm arctic cable for the 240v flexible extension to the transformer or even add another dedicated to the lights … saves going dark when they trip the transformer

[saveasteading]

Thanks. I didn't know HD 240 existed.

I now see them advertised at all sorts of amperages if that's a word.

 

should I be looking for one that will reach the middle of the building?

what amps might be a sensible spec? I see so far 13, 16 and 32A.

will these be 3 pin or the round socket sort?  

in the building what will we have? a single 110V transformer or a multi socket one, or as many singles as are wanted?

is blue a preferred colour to indicate what the cable is? i see them in blue or black and even orange.

 

if i am understanding.

 

In either the garage or canteen we plug a 240V domestic type plug into a normal socket. perhaps with a conveter from domestic plug to round.

We then take that cable to the barn, perhaps well above ground to avoid accidents. Blue or orange would be safer than black.

in the barn it is dry now, or soon will be, so we simply have a 240V socket into which we plug a transformer. thereafter the guys just plug in what they want.

Perhaps @markc  's idea too.  so the 240V for most purposes but retain the trailing separate 110V to a few lights,  in case of a local trip.

 

[saveasteading]

is it as simple as this, or 2 of these\?

 

https://www.screwfix.com/p/masterplug-ldct2513bq-4-xd-13a-4-gang-25m-cable-reel-240v/54615

[markc]

54 minutes ago, saveasteading said:

is it as simple as this, or 2 of these\?

 

https://www.screwfix.com/p/masterplug-ldct2513bq-4-xd-13a-4-gang-25m-cable-reel-240v/54615

Yes, these are decent quality, couple of those so you are running parallel supplies, transformer on each and you are sorted.

[ProDave]

1 hour ago, saveasteading said:

is it as simple as this, or 2 of these\?

 

https://www.screwfix.com/p/masterplug-ldct2513bq-4-xd-13a-4-gang-25m-cable-reel-240v/54615

Conductor area 1.25mm  No I would not buy that.

 

My long 250V extension lead is self made using 5 core 2.5mm with 2 cores in parallel for both L and N.

 

I doubt you will find a pre made lead with 2.5mm cable, read the small print.

 

Buy a drum of 3 core 2.5mm flex and make your own lead to the length you want with no joins and a good quality plug and socket each end.

[garrymartin]

59 minutes ago, saveasteading said:

is it as simple as this, or 2 of these\?

 

https://www.screwfix.com/p/masterplug-ldct2513bq-4-xd-13a-4-gang-25m-cable-reel-240v/54615

The cable used in those is listed as 1.25mm2 - you should go for something much heavier duty. Minimum 2.5mm2 considering the distance and use.

[markc]

Just now, garrymartin said:

The cable used in those is listed as 1.25mm2 - you should go for something much heavier duty. Minimum 2.5mm2 considering the distance and use.

Really, the ones I picked up are 2.5mm, sorry @saveasteading I just opened the link but didn’t check details. You do need 2.5mm2 minimum on the cable at 25m long

[Temp]

I make my own extension cables when I can because commercial manufacturers are under cost pressures to use as skinny a wire as they can get away with. 

[Redbeard]

If you make your own it also has the possible advantage that it will not be left on a reel. Did anyone mention ensuring the reel is fully unwound? A hefty draw on a part-wound ext'n lead shows what a good resistor it makes... (Egg-sucking and grandmothers not intended!)

[garrymartin]

Something like this; 2.5mm2 3-core with 4 sockets https://www.amazon.co.uk/Portable-Blue-Extension-Lead-Cable/dp/B0FVZH1JQD

 

[-rick-]

That one makes my spidey senses tingle. As in is it a dodgy Chinesium one?

 

It's also available at close to half the price on polybound.co.uk (the claimed manufacturer - who seem to specialise in resin bound surfaces).

 

https://polybound.co.uk/product/tools-equipment/25m-blue-extension-cable-reel/

Edited 2 hours ago by -rick-

[garrymartin]

8 minutes ago, -rick- said:

That one makes my spidey senses tingle. As in is it a dodgy Chinesium one?

 

It was just an example. To be honest, I don't know how they can sell a 25m extension cable with 2.5mm2 cores for that price. Costs more than that to buy just the cable! But heh, it's a UK company, and has both CE and UKCA marking. Might just be a bargain!

 

(NOTE they also sell it as a kit with a 5kVA 110V transformer, so specifically for the purpose @saveasteading is looking to us it)

[-rick-]

22 minutes ago, garrymartin said:

To be honest, I don't know how they can sell a 25m extension cable with 2.5mm2 cores for that price.

 

My worry would be it's 2.5mm2 copper coated aluminium. Still probably better than the 1.25mm2 copper ones mentioned earlier, but nowhere near 2.5mm2 copper.

Edited 2 hours ago by -rick-

[saveasteading]

Thanks all. This is all very helpful.

I did some electrical engineering at school,  just as an extra subject. My teacher couldn't believe how bad I was at it when i was good with other sorts of engineering. so thanks for the patience.

 

We are supervising so can ensure that a reel is unwound. The reel, has the advantage of easy relocation, either out of the way, or to suit room arrangements as they get built.

We can brief the workers too and label the ends with instructions.

 

The point about checking the spec is good, as some give very few details.

I can see that a non-reel somehow seems more credible. and could be fastened to a wall: but I'm amazed that I haven't found any ready-made.

On this basis we should locate the outlet fairly centrally, then  an adjacent transformer and no other sockets. shortest distances for 110 cables from there.

 

this is £3/m cur to any length, so a reel of 25m at either £50 or £30 seems surprising. 

 

 

 

 

we have plenty of transformers, I think through often needing them in a hurry then back to store after use.

 

 

@ProDave 

what type of plugs would be best for your way? Or domestic one ended , round the other?  CEE seems to be the term, and they look somehow more credible to the amateur (which our demanding, but seemingly corect)  joiners are in this regard.

are they straightforward to connect. I've done armoured and surely anything is easy compared to that?

what does one do with the multiple L and N cables? Just join them in as if it was a 3 core cable?

Id like to buy the cable in blue as it is clear what it is and easier to see, but can't find any.

 

can I just use 2 of this and join them?  

 

 

OR How about this for  a quick fix. I buy 2 of the reels shown above. Thence they have lots of capacity and can be set in different spots. or 3, with one extending off the other to the other end of the building?     Call 'silly' if it is so!

 

 

 

[Oz07]

Whats the insurance or safety implications of the 240v lead being run through your site? Could you use one of the big daddy transformers instead or does that not improve the amount of power taken down 1 110v lead?