Extending cables underfloor

bobsmate · 20 Nov 2009

I'm at a job where i've been asked to extend same cables, now unfortunatly this must be done under the floor. I know that Junction boxes are now not allowed, and i would use crimps in a choc box, but recently i found out that apprently crimps aren't very good on solid cables and only work well on stranded cable. Whats the best way then to make these connections and is what i've heard about the crimps true or would it be perfectly safe to use them?

Edit: Just seen a different thread on the same page answering my question, only problem is one of the joint boxes has more than 1 pair of cables in (a spur), so what then would be the best option?

ban-all-sheds · 20 Nov 2009

bobsmate said:
I'm at a job where i've been asked to extend same cables, now unfortunatly this must be done under the floor.

If you have access under the floor why can't the cables be replaced with ones of the right length?

I know that Junction boxes are now not allowed,

"Now"? They've had the same restrictions (not prohibition) on their use for at least 18 years.

and i would use crimps in a choc box, but recently i found out that apprently crimps aren't very good on solid cables and only work well on stranded cable.

Where did you find this out?

Whats the best way then to make these connections and is what i've heard about the crimps true or would it be perfectly safe to use them?

They'll be fine if properly done.

Edit: Just seen a different thread on the same page answering my question, only problem is one of the joint boxes has more than 1 pair of cables in (a spur), so what then would be the best option?

Replace the cables.

bobsmate · 20 Nov 2009

ban-all-sheds said:
bobsmate said:

I'm at a job where i've been asked to extend same cables, now unfortunatly this must be done under the floor.

Click to expand...

If you have access under the floor why can't the cables be replaced with ones of the right length?

As i only have access to a certain part of the floor area.

and i would use crimps in a choc box, but recently i found out that apprently crimps aren't very good on solid cables and only work well on stranded cable.

Click to expand...

Where did you find this out?

Looking around on another website

Whats the best way then to make these connections and is what i've heard about the crimps true or would it be perfectly safe to use them?

Click to expand...

They'll be fine if properly done.

Then this is what i shall do.

Edit: Just seen a different thread on the same page answering my question, only problem is one of the joint boxes has more than 1 pair of cables in (a spur), so what then would be the best option?

Click to expand...

Replace the cables.

Is there any other way as i really son't no if i'm going to be able to replace it because of the access i have to certain parts underneath the floor. I take it you can't put 3 wires into one crimp?

bloxy · 20 Nov 2009

What about these?
http://www.tlc-direct.co.uk/Products/ASJ803.html

Hager claim they meet 17th edition.
http://www.tlc-direct.co.uk/Technical/DataSheets/Hager/JB_Guide.pdf

ban-all-sheds · 20 Nov 2009

That claim has been widely discussed here, and the consensus is that it's bogus.

bobsmate · 20 Nov 2009

Are they those push in connectors you sometimes find in lights? If so even if they did comply then i wouldn't put them in as i wouldn't feel safe.

But thanks anyway.

ban-all-sheds · 20 Nov 2009

They are, and I don't blame you.

And IMO (and others too) the manufacturers are taking a flyer on this "maintenance free" malarkey when that concept doesn't appear in the regulation concerning concealed joints.

bloxy · 20 Nov 2009

bobsmate said:
Are they those push in connectors you sometimes find in lights? If

The Ashley ones push in, there is obviously a barb arrangement because you can't then withdraw the cable, once all connections are in place you push down the tab on top with a screwdriver, this compresses the joint and makes it permanent, much like you do do when squeeze up a crimp.

Reading back through this forum a few years ago crimps were being frowned on as unsuitable for permanent joints, funny how times change.

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Extending cables underfloor

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