Refrigerated lorry hook up points

[slocm3105]

Has anyone got any experience of wiring these? I have been asked to wire up 6 hook up points for Thermo King refrigerated container lorries. They have a start up current of 70A and full load current of 17A. There is an existing 3 phase distribution board with one 3 phase way left on it. I was hoping to use this spare way to feed a seperate consumer unit for the 6 container circuits. The cable run is about 50m and am wondering if anyone has any suggestions?

 

[slocm3105]

These hook up points will be mounted on a concrete wall outside and wired in SWA. Will i need to wire a starter or anything to account for the high start up load?

 

[mogga]

no need for started last time we did them it was 32a D type if memory serves me correctly

 

[slocm3105]

thanks mate, I imagine you ran seperate circuit for each one? And did you use Lewden CEE type 32A 415V socket outlets?

 

[slocm3105]

also did you run 4mm or 6mm 4 core SWA to them?

 

[mogga]

cable size will require to be worked out length ect ect As for sockets they were MK Commando interlocked each had seperate circuit

 

[slocm3105]

at my sub DB is it fine to just have a 125A 4 pole incomer and then 32a 3 pole MCB's type D for each circuit? RCD protection is not required I believe.

 

[Knobhead]

RCD protection may not be required but I personally would fit it. The trailer cables can get in a bit of a state, wagon drivers aren’t noted for being delicate.

 

[mogga]

that was one of the regular jobs at depot we maintained "Check trailer leads faulty" should have read"Check trailer leads run over driven away without unplugging and generaly abused !" the leads we used were made up of SY Cable and withstood a fair bit but deffo fit RCDsS either in db or rcd commando sockets

 

[bomjac]

Silly question, but do the lorries require single phase or 3 phase power (220V or 415V) ?

I would also agree with the fitting of RCD/RCBO type sockets. Classing your drivers as "trained personell" and training them in the proper use of the sockets / plugs would also mean that you can get away with 100mA RCDs which may eliminate nuisance tripping found on 30mA RCDs with startup currents. My reasoning being that a wagon is "portable equipment" that could be expected to be towed away with the plug still attached !

 

[Knobhead]

When ordering the new equipment add spare pugs and sockets. Keep in mind whatever you do, the drivers will find a way of wrecking it!
With regard to the type of socket, these trailers will be used at other depots so be sure as to the type you fit.

When positioning the sockets be sure they’re out of harms way. 38T wagon Vs commando socket = No Contest!

There was a post on here a while ago started by a wagon driver, it made good reading.

 

[Knobhead]

Have a look at http://www.electriciansforums.net/c...35023-3-phase-electric-motor-road-tanker.html

 

[silva.foxx]

What happens with respect to phase rotation?

Is there a device on the fridge system that ensures correct rotation?

Irrelevant response to OP's question... but just thought I'd ask.

 

[Knobhead]

It’s a very valid point. One that I’ve seen cause several f**k ups.

 

[bomjac]

I have seen 3 phase plugs that come with 2 of the phase pins on a rotatable swivel, so you can swap the rotation without disconecting wires or opening panels/DBs up. Id like to think that such an expensive piece of kit as a refrigerated wagon has some form of correct phase detection in it - The A60 pressurised cabs we get offshore all have an indication of correct or wrong phasing. If its wrong then the supply panel is locked out until you correct it

 

[Knobhead]

This may make you laugh. As an apprentice I was appointed as “assistant” site engineer on a new plant. Came the great day of switching on power to the MCC, Oh dear what a f**k up. The contracting foreman was adamant all drives will run the correct way.
A motor connected RYB to ABC will turn CW when looking at the shaft.
I was going purple around the gills when I explained to him the works had it’s own power station and it ran opposite to the grid! Every (over 100) motor had to be changed at the terminal box.

 

[Inteificio]

Why was the generator run back to front?

 

[malcolmsanford]

What happens with respect to phase rotation?

Is there a device on the fridge system that ensures correct rotation?

Irrelevant response to OP's question... but just thought I'd ask.

All the ones I have done Silva had phase failure relays on the units for phase rotation and single phasing problems.

 

[Knobhead]

The original two power satiations were installed in the early 1930’s. They were linked by two 11KV lines, which had the distinction of the longest spans in the country at that time. Various other plants were connected of the two main interconnects. At that time the company had over 100 different sites in the area. There was no connection to the grid then, there wasn’t one to speak of. So when the day came to connect to the grid we were going backwards in relation to the rest of the country! Simple answer was to swap the boards phases over. The confusion lasts up until this day.