Thread: How to attach Cabling trayway to an RSJ?

Use the Ericsson channel. Make some flat bar sections that sandwich the channel flanges possibly.

Nigel / RT,
Telstra also, 43 yrs, 47 weeks, started in Jan 1975 at North Strathfield. Assigned to Telegraph Install in 76 installing telex machines till August 88. Went to Data cabling installing RASS, Dcris & TRAC etc, in sales offices & exchanges for 2 years. From there it was Data Install, installing NTU's & modems. Feb 97 stated installing Cisco gear customers & first maintenance for BigPond as well. Also installed Mega-links & ISDN 10/20/30. Last 3-4 yrs was a major comms network Australia wide. Last 18 yrs at Regents Park here in Sydney. Redundancy finally Dec 2018.

John Q

Nigel, did you know Frank Nische.

Originally Posted by JohnQ

Nigel, did you know Frank Nische.

We had a Frank who was a team GA, but I don't remember his surname.

He was one of Data's to engineers and member of the CCITT.

Originally Posted by nigelpearson

Option 2:
Attachment 386267

[...]

So, more experienced comrades, any suggestions?

The german way is option 2, but with bars made of c-profiled steel to make it more ridgit

RacingTadpole and JohnQ, here's a challenge for you. What are these for:

IMG_0668.jpg

I thought they were clamps for this trayway, but the M8 set screws only just clear the depth of the clamp.
The captive nut slides, so something strangely adjustable.




P.S. Tried to buy some beam clamps. These cast ones:
Screen Shot 2020-05-06 at 6.35.15 pm.jpg are reasonable – between $8 and $12.

The one-piece ones for channel strut, however:
Screen Shot 2020-05-06 at 6.35.02 pm.jpgare crazy – $37 plus GST each.

Looks like I will be fabricating

The clamps are for tel-tray. Later exchange builds (mostly H2/H3 heat management) had tel-tray platforms you could walk on above the racks. Tel-tray is 150mm wide cable tray with the cable tie bumps pressed into in the inverse of the orange stuff you have, ie instead of the bumps are pushed up out the back of it. It’s mounted flanges down and the clips you have fit over the inside edge of the flange and the bolt goes through the slotted unistrut into the captive nut to secure the tray and stop it skating off the unistrut.

Ive literally rattled up thousands of them.

Looking back at your first post and the picture of the Macgyver hardware, do you have a supply of those grey clamps that are holding the DDF hardware onto the beam?

Originally Posted by racingtadpole

do you have a supply of those grey clamps

Yep, 14 pairs:IMG_0042.jpg



I think they are floor grid/mesh clamps. My MacGyver solution was to grind a locating slot in the long one, drill 2 holes in the strap, and bolt up:

IMG_0043.jpg




My worry was just the bend in the strap from the middle hole (closest to the cantilevered tray):
IMG_0044.jpg



I think the tension required to clamp securely was too high. Many things would help;

1. Grind the slot deeper, so the clamp was flatter on the beam flange.
2. Thick washers between strap and clamp.
3. Use two MDF straps. Line up the dimples, and viola

So, to wrap up, I did end up using the flat bar, and several other leftovers. Here is the "design":

IMG_0718.jpgIMG_0719.jpg


The flat bar is actually 25x6mm and fairly soft steel. Its nowhere near as tough as angle iron or strut would be, so I decided to use as many as I had the clamps for – 15 over an 8m span – basically over-engineering it.

So, start with the bar. Notice there are two small holes on one end. They originally had little bits of angle iron bolted onto them. I shortened the angle iron, and attached on the outside edge (to use as a locating stop for the trayway):
IMG_0715.jpgIMG_0716.jpg


Then attach the spring clamp, which loosely holds the back of the bar onto the i-beam, and grind/file a step to fit the flat bar:
IMG_0717.jpg

IMG_0720.jpg


A few more bolts and nuts, and viola:
IMG_0721.jpgIMG_0722.jpgIMG_0723.jpg




...still working on the rest of the span, as I am cleaning thick dust as I go:
IMG_0725.jpg

a drop-down channel to the middle of the floor:
IMG_20200606_153226_946.jpg IMG_20200606_161201_778.jpg IMG_20200606_161444_017.jpg


Bottom edge is a little above head height. I will bolt a bunch of power outlets, and a few air quick connect sockets, in the channel or on the back

That turned out quite good, call that a repurposing success.

For the run down to my breaker box, I wanted to have a gentler than 90° bend on the cables, so...

1. Slit the tray, guess 45° and cut a cardboard template:
IMG_20200610_120317_332.jpg

2. Fab' a bracket from an old wheel clamp back plate:
IMG_20200610_132537_041.jpgIMG_20200610_161745_334.jpg

3. The horizontal tray is offset a bit from the vertical run, so one side gets flattened, and an odd bracket:
IMG_20200610_161818_965.jpg

4. Installed:
IMG_0783.jpg




P.S. Shortening some live conduit with a huge, rusty, old plumbing pipe cutter:
IMG_0788.jpg

Nigel

Nothing wrong with CAD, Cardboard Added Design. Works well.

JohnQ