Singles in conduit. Domestic

Having taken on board the advice here I am now going to use pyro for the lighting circuits in the loft area. This will increase the cost and time involved but will be the best method in the long term.
 
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Having taken on board the advice here I am now going to use pyro for the lighting circuits in the loft area. This will increase the cost and time involved but will be the best method in the long term.
As a matter of interest (I've never used pyro), how does one deal with the terminations in a domestic lighting circuit (switches, light fittings etc.) when wiring is in pyro? Does one have to use JBs of some sort to convert to T&E, or does one attempt to terminate the pyro in the fittings/accessories?

Kind Regards,John.
 
pyro to the fittings..
terminated into couplers on the backboxes so that the end of the gland does not protrude into the box..
 
pyro to the fittings..
terminated into couplers on the backboxes so that the end of the gland does not protrude into the box..
Ah, I see - thanks. That presumably means that one needs to create a reasonable sized hole adjacent to the backbox (if it's in plaster/masonry)?

Kind Regards, John.
 
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Had a conversation with the applications department of one of the manufactures of mineral insulated cable and all my questions have been answered.

The termination to ceiling roses is not as complicated as it seems. Provided the cable is clamped to prevent movement a screw on pot with earth lead inside a metal enclosure is sufficient in those applications where the installation does not have to survive a fire
 
Your insurance company and/or Local Authority may have additional requirements where thatched properties are concerned they often specify fire resistant containment and sometimes void smoke detection.

The majority of modern thatches are ammonia treated as to be flame retardent and many now are seed-free so rodent damage is not so relevant as it was in the past, though I would still take the attack of fauna into consideration.
 
pyro to the fittings..
terminated into couplers on the backboxes so that the end of the gland does not protrude into the box..
Why is that needed?

1) Space.

2) The wires from the gland will not be strained or bent at right angles out of the pot. They will travel straight away from the pot down the coupler.
 
Not that I've ever seen.


Here's the difference between using a coupler or not.

IMGP3282new.jpg

With


IMGP3118-1.jpg

Without



It's amazing what's in my archives!!
 
Can you get brass couplers?

I've never seen such an item, and initial thoughts are that brass would be too soft a metal and it would 'bell out' too easily when tightened, also would be expensive

I suppose if you really wanted brass you could try and machine one up yourself, probably have to make it quite a bit thicker than standard couplers or it would just break!

How about having a coupler electro-plated?
 
The termination to ceiling roses is not as complicated as it seems. Provided the cable is clamped to prevent movement a screw on pot with earth lead inside a metal enclosure is sufficient in those applications where the installation does not have to survive a fire

Bernard,

I'd recommend you use an appropiate BESA box in the attic to suit number ans direction of cables... if looking in and out these are likely to be trouser or tee boxes you'll need for most, fitted to a batten fixed between two joints, then use an extension ring to extend the box to flush with the ceiling
 
Can you still get flush MI BESA boxes? I've had a quick google with no joy.
 
fitted to a batten fixed between two joints,
The "joists" are very old round timbers just large enough to support the original lath and plaster ceiling. It is un-likely the joists will safely support the weight of a person. So work above the ceiling has to be limited to that which does not require a person being there. Conservation means the absolute minimum of disturbance of the ceiling.

This was the reason for using conduit which could be manipulated from the access hatch in the next room until its end was close enough to the hole in the ceiling to enable the cable to be fished for through the hole and then guide the 90 degree bend at the end of the conduit through the hole.
 

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