Advice needed on fitting metal conduit

[ringer]

Not done industrial installation before and will be looking at a job in an automotive workshop on Tuesday needing (probably) about 10 metres of 20mm conduit, including up and over a doorway. First time for me with metal conduit so a few questions, if you don't mind....

There is existing metal trunking on part of the wall and will be using conduit to extend this to equipment I will be installing. Is this dome plate a suitable method of joining the conduit to the trunking? If so, do I use self-tappers or nut&bolt to fix it?

Any advice on making 20mm holes in trunking to run cables into the conduit (apart from using a bloody big drill bit!)? e.g. 25mm hole saw and cover with a suitable accessory (such as the dome plate)? Do I need to fit grommets etc to protect sharp edges?

Am assuming I will need to cut conduit to length then form threads for couplers / elbows / joining onto boxes, so will I need a die and die holder?

Do I need to use these locknuts on all thread/screwed in connections?

Planning on using saddles to support the conduit. Will there be space to turn locknuts?

Am thinking any joints needed will be made with crimps and heatshrink. Or is there suitable junction boxes I can use?

Suggestions please on protecting cables (singles) as they exit conduit. Do I terminate conduit with a box, and make hole in a lid and fit grommet? And what about protecting the singles between conduit and equipment?

And any tips/advice/things to watch out for?

That ended up being a lot of questions, and they may seem pretty basic to you, but we've all got to start somewhere, so answers will be much appreciated

 

[Darkwood]

think you going astray with dome fitting just drill hole in trunking and brass bush and coupler to link to conduit no locknuts needed saddle conduit to destination then again brass bush and coupler in.

 

[Hawk81]

these are what you need Buy Newey & Eyre Flange Coupler, Steel, Galvanised, 25mm - CFCOUPF25GV either in 20mm or 25mm. if you are doing any cuts and joints and bends you will need a pipe bender and die set. dont put steel conduit into an ordinary vice as is will crush it and it will lose is round shape

 

[Hawk81]

as for drilling the steel trunking you need Electricians Holesaw Kit - Screwfix.com, Where the Trade Buys

 

[malcolmsanford]

The guys seems to have covered everything. As it's a auotmotive workshop are you going to use galv conduit? I would use a class 4 for the enviroment.

Are you going to run a seperate CPC? As you know you can use conduit as a CPC, though modern techniques have seem to veer towards running a cpc. as your not use to conduit may pay to run a seperate CPC.

As for going over the door you can do your own 90 bends or even a double set, but as said you'll need a vice for that or the old "Hicky" block. You can buy elbows and do it that way if you like but it can run expensive.

Drilling into the trunking yes use a 20mm hole saw easily got. A tip though get a flat piece of MDF perhaps 6" square and about 9mm thick. Place this ontop of the cable inside the trunking under where your drilling. Nothing as embaressing as cutting through the trunking with the drill and also the cables under neath in the trunking.

As for connecting the appliances. Terminate the conduit it a "Through" box. Then get some 20mm^ Kopex and glands fit this to the second side of the 'Through" box and onto the applaince.

 

[ringer]

Thanks for the replies guys - much appreciated. Think I will eat the cost of the elbows this time Malcolm and practice bending conduit at home when I have time, rather than mucking it up in front of the customer

 

[telectrix]

a tip i've always used...... don't try to bend conduit to fit exact to trunking etc. bend it so it's a bit longer than you want then cut and thread.