MI cable

[Adam_151]

Doing MI at college atm,

About got the hang of stripping it (with the rotary stripper, didn't get on too well with the cutters and T-bar method), fitting the pot, filling it crimping it and glanding it off into an enclosure, but anyone got any advice on getting it looking neat, mine is all wobby (and I assure you I was sober ) just wondered if there is any tricks to it other than practice? (to getting it neat)

Also, when glanding it off into socket boxes etc, we seem to always use a conduit coupler and bush, but I'm sure I've seen it straight into boxes before... is there anything dodgy about not using the coupler, or is it just that you have to take more care that pot doesn't get in the way?

Oh, is there a reason why some pots have earth wires on them and some don't?

 

[ricicle]

To aid MI straightness it helps if its fairly straight off the roll/coil in the first place.With practise you can kneed a piece of MI into line with fingers.hands etc.As for couplers it is a fairly common installation method and I think it is to keep the gland up out of the box to increase space.
Pots with earth tags are to ensure continuity when the copper sheath is used as the cpc

 

[RF Lighting]

I presume it is the pyro cable that is wobbly (not the gland etc)

The easiest way is to keep it straight as it comes off the drum, but if it comes pre knackered as tends to be the case at college, then srraighten it as best you can wuth your fingers, then you could manufacture a pyro straightning block out of a bit of wood with a groove cut down its length, and tap this with a hammer along the length of the pyro.

There is no need to use a bush and coupling, except it allows you a little more play in the lenth of the pyro as the pot can go anywhere in the coupling without fouling the accesory.

It is also easier to line the coupling with the knockout and install a bush than having to bend the pyro and bend it back to insert a gland straight into the socket.

Pot tails allow you to get a 'proper' earth connection from the pryo sheath rather than relying on whatever bit of metal you have glanded the pyro onto.

 

[ricicle]

Nice Piccy RF

 

[RF Lighting]

drew it my self

 

[breezer]

we used to have a "roller" to remove kinks. but getting unwinding the roll as you install it, i have never had it go kinked.


oh, the roller was a series of wheels top and bottom and some handles

 

[Big_Spark]

That is all well and good unless you have 3L1.5 and up, as it doesn't come on a drum for some insane reason, and it can get all out of sorts.

You can buy actual straightening tools, but they are stupidly expensive these days. RF's idea for the wooden block works ok. I personally use a rubber mallet and a block of wood..but it's horses for courses...

 

[Adam_151]

Think we have a straightening tool at college, we dont use it, but I think we have one, lol

I think quite a few of the kinks and uneveness are introduced when I move the end away from the surface to strip it and make off the pot tbh, and vibration from actually working on making the end probably doesn't help much

(yes with it being college, some of it is pre-bent a little )

 

[securespark]

With practise you can kneed a piece of MI into line with fingers.hands etc.

The mind BOGGLES!!

 

[Pensdown]

Oh, is there a reason why some pots have earth wires on them and some don't?

Above is another example of when you would use a flying earth pot. Because this MI back box doesn't require a gland, the only earth connection is via the pot clamp inside the back box. This clamp connection is not good enough to earth the sheath or allow the sheath to be used as the sole earth so an earthed pot gets over the problem.

I think quite a few of the kinks and uneveness are introduced when I move the end away from the surface to strip it and make off the pot tbh, and vibration from actually working on making the end probably doesn't help much

If you dress the cable and then leave the last 4 or 5 clips off it not only makes it easier to make off it's also easier to get the gland into the coupler without bending it.