my boss wants me to "fix" a pump. The techs claim they have to "jiggle" the cord to get it to work.


My first thought was a wire short, until I opened the switch:





I'm no electical expert, but this seems excessive for normal wear and tear... even for a "really old" switch



Do I need to just swap out for a new switch? Or does this pump have bigger problems

Needs a grounding rod to drain off the excess electricity.

Looks like it arced to me.  Needs replaced

From the other side of the switch... I'm not the first one to "repair" this switch. Why do I feel like I'm getting bubba's sloppy seconds... or thirds...

Put a new switch in. Has been arcing for some time and slowly eating away at the contacts.

Something is causing the switch not to fully close or open causing arc. No one wondered why it was getting hot?

We were replacing some 30 amp relays last week for a greenhouse temperature control. Couldn't figure out why the relays wouldn't pull in, just chatter. I'm not sure what we did, one relay finally pulled in enough to have this neat green fire erupt inside. It was only a 30 amp relay, but it's enough to tighten your sphincter.

Chemistry techs are not that smart when it comes to electricity....

Replace the switch, that will be $150, we accept CC or checks.

SPNI.  That switch is fried.

Probably just needs a new switch.

Check the resistance and inductance of the coil and compare to spec if worried about the motor.

that switch is breaking the neutral (white). should be breaking the hot (black).
I never switch neutrals

I'm not good with three phase AC. Explain?
 


ETA: are you saying the idiot before me installed this switch fucky?

Single phase, and the white wire should be straight through and the black going to the switch terminals assuming the wiring is correct on the plug end and the pump end.

Umm that is not 3 phase. The black - ungrounded (hopefully!) conductor should be switched. The white - grounded conductor (not green ground wire) should not be interrupted. This is assuming it is a 120V circuit. I have seen more than 1 240V circuit where the white conductor was used as an ungrounded conductor.



And I agree, make sure you have a properly rated switch.





 

I'd replace the cord along with the switch.  Better yet, replace the cord and mount a switch on the pump itself.

Uhhhh, are you sure your qualified to change out that switch?

As qualified as anyone on location

I'm thinking the mysteries of alternating current might be too much for you.

Hi I'm an electrician look at the pump it should have a name plate with the voltage and amperage listed on it if it's less than 6 amps an inline switch from home depot is $4 it will work I'm assuming it's a small air or water pump maybe a half horse power  http://m.homedepot.com/p/Westinghouse-Brown-Feed-Through-On-Off-Switch-7050600/204836051

It took more time to take pics and post a thread than it would have to cut a new switch in...

Do not need to know the "mysteries"

Already confirmed the switch was wired improperly (confirmed the white is indeed wired to the neutral prong)


Already looking for a switch that can handle the spec of the pump.


I can do basic clipping and re stripping of the existing wire for a clean connection


All I needed to really know was whether or not the wear patterns were an indication of more complicated or severe damage. I believe I have that answer now.

Actually your not far off


It's a Dayton 1/3 hp vac pump.


 

That switch is close, but not quite strong enough

Here's the way to look at the point about switching the black wire.  Imagine you want to use water to spin a paddle wheel.  You take a hose, run it out to the paddle wheel in a closed box, and run another hose to drain the water.  You want to be able to control the paddle wheel with a faucet.  You could put the faucet in the hose that delivered the water, or in the hose that drained the water- either one would work.  Let's say the hoses were running through your house.  If you put the faucet in the return hose, there would be water pressure all the time in the delivery hose, the paddle wheel box and the return hose, right up to the faucet.  It any portion of the circuit sprung a leak, right up to the faucet, your house would flood.  But if you put the faucet in the supply hose, there's no water pressure in the supply hose (after the faucet, of course), the paddle wheel box or the return hose unless the faucet is turned on.  There's much less chance of flooding.  Switching back to electricity, the water pressure is an energized circuit, and a leak is a ground or line fault, possibly through you.  The faucet is the switch, and the black wire is the supply hose.  The smaller the portion of energized circuit, generally the better off you are.  Which is why almost anything with a switch has a polarized plug, to make sure the switched line is the black or hot wire.

I figured that was about the gist of it, but that is an awesome analogy. And I learned today.