Non-PLC Question For Help

Hello Everybody.

I would not post this here if I did not really need some help with this. I appreciate your patience. I normally use this site for PLC and Automation-related questions/answers. I am a maintenance manager for a food processing company and I have inherited a problem that I need your help with. Here is the problem. We have an outside area that we park trucks in overnight and we then plug their reefers (refrigeration unit) into a SO-corded female receptacle (LEVITON CS8364C - twist-loc). The mating part to this receptacle is on a cord connected to the reefer. Drivers are often climbing into their trucks and absentmindedly driving away with this power supply connected, thus ripping the SO-cord from the electrical disconnect box and causing a very dangerous situation. I need to come-up a "break-away-type" of device, if there is such a thing, to replace the LEVITON CS8364C, if possible. Please let me know your thoughts.

Thank You!

Michael

Hi Michael,

A few suggestions come to mind if the drivers are check-in receiving have them sign a form about charging them damage fees if they drive away. This can trigger a warning in their mind. You might not want to charge them, but this could bring it to their attention. Either way I know drivers are very fatigue most of the time.

You could give them a sign to hang on the steering wheel in red to remind them about the plug before the drive away.

Lastly and probably more important having worked in a warehouse, receiving docks have locking mechanism for trucks, why not lock the truck until the driver has made sure the plug is taken off?

Good luck with finding the right solution, but I think fixing the human behavior here is the actual issue in my opinion.

Have a look here we used these type for 480V, but they have them in several configurations including 120V, and 250V.
These are straight push, but they have a twist if you which to seal it. I guess you could take these off to prevent drivers from locking it.
And if they do drive away it should just come right off the outlet, and thus the question arises if you want drivers to be driving around with a chord still plugged in their truck.

http://www.leviton.com/en/products/electrical-wiring-devices/pin-sleeve-devices-iec-60309
http://www.leviton.com/en/products/...ces/pin--sleeve-devices--iec-60309/connectors

What voltage are you dealing with?

kamenges said:

What voltage are you dealing with?

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The part number he listed takes you to a Twist-Lock® Insulgrip® Connector Body, 50A 3-Phase 250V, 3P4W, Non-NEMA, Black and White

Just a thought-starter for you. Amphenol offers a MIL spec 'Breakaway Fail Safe Lanyard Release Plug'. I don't know if they offer sizes up to 50A like the Leviton, but if they do:

You wouldn't replace the Leviton plug, but put the breakaway in-line close to the junction box, where you would anchor the lanyard. Add two poles to the connector and use a load side jumper to complete an alarm circuit hold-off, so that an audible/beacon alarm can be sounded when the connector separates.

Then invoice or back charge any shipper whose driver takes off with the connector at least $750 for a replacement cordset. There won't be many repeats.

Perhaps a little low-tech, but how about having a dirty great big wheel chock attached to the plug?

I would install a relay in each vehicle that disables the engine-start circuit when AC power is connected.

MasterBlaster said:

I would install a relay in each vehicle that disables the engine-start circuit when AC power is connected.

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The trucks are probably idling while driver is in it. This would probably make for some angry drivers.

actually I like the wheel-chock idea better - but here's another low-tech approach ...

how about the "clothespin" idea that I've got my wife using for her cell phone ...

basically we keep a clothespin clipped to the cord on the cell phone charger ... whenever she plugs in the phone – the clothespin IMMEDIATELY gets clipped onto the handle of her purse ...

so ...

if she grabs the purse on the way out the door, and she feels the clothespin – she runs back to the kitchen and grabs the phone ...

so maybe ...

something like a big bright red "Don't Forget The Plug" sign – secured to one of those metal clothespin-type clamps from Lowes (used for holding stuff till the glue sets) ...

keep the sign clamped to either the cord (when it's not connected) – or the handle on the truck driver's door - or maybe to the windshield wiper ...

Use the electric "Dryer" type plug with flat blades. Most are right angle to fit behind the dryer. Here's a straight Industrial style at Home Depot.

Seems the fire truck industry has a solution for you.

http://www.kussmaul.com/automatic ejectors index.html

Zip tie the ignition key to the cord cap.

Regardless of human behavior, they have to unplug the cord to get the key.

Your problem then shifts to who's responsible for putting the key on the cord.

Highest cost is accountability.

Welcome to the forum.

Can you not have a set of wheel chocks on the same side as the ac connection point?
also, have a chain connected from the chocks to the ac cable.
the driver cannot move because of the chocks, when he removes the chocks, he sees the cable tied to the chocks and also the ac connection.

as suggested, have all drivers sign an acknowledgement stating that they will
be responsible for any and all damages caused by their failure to disconnect from the ac power.

james

It would be great if they had a forklift style plug for this application. the plug was on their end, and it would just yank out and get shredded to oblivion, and then they couldn't plug in at the next place.

I think they would learn quickly.

I've come up against this in the past, it's not at all uncommon.

• The refers are typically plugged in and running long before the truckers arrive to pick up the load, so chocking the tires would require a warehouse worker to meet and greet each truck, and they don't really do that. The truckers pull up, connect their hitch and as soon as the trailer is full, they drive off.
• You cannot change the connectors, they are industry standards so that the trailers can be plugged in wherever they go.
• You cannot disable the ignition, the truckers run the engines for heat and power for the cab, these plugs are on the refer units of the TRAILERS, not the cabs. The drives are typically independent contractors, they are not going to allow anyone to install any ignition switches either.

What I helped implement at one site where this was a big issue was to have a current sensing relay on the power circuit feeding each plug, and that relay controls a green/red "traffic light" in each bay of the warehouse, that hangs out to where the driver sees it in front of him. Then on that light is a sign telling them that driving off under a red light will trigger a camera to take a picture of their plate and fine them $500 to repair the cord. Put a stop to it immediately. In many places the traffic light is already part of the dock, so the trucker normally looks in his mirror to know when the trailer is full because the light turns green when the loading is done. So if you simply don't allow the light to turn green until the cord is unplugged, they don't leave. On those you could put up the sign with the lettering reversed so that it reads correctly in his mirror.