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Bead Blaster trips gfi outlets

metal-ica

Cast Iron
Joined
Jan 19, 2019
I have a bead blaster located outside in a covered and "enclosed " area. Think carport.

I've been using an extension cord and decided it's time to run a dedicated circuit and since it's outside it's my understanding it needs to be a gfci receptacle. Problem is it trips the instant I plug the machine into a gfci outlet. It works fine with the standard outlets but trips even before powering on the machine. I know the problem isn't on the gfci side because I've tried it on multiple outlets / circuits. I'm guessing there is a ground fault or something on the machine side of things but it works beautifully with a regular outlet.

Is this an accident waiting to happen or is it ok to run it on a regular outlet even though it's technically outdoors?
 
I have a bead blaster located outside in a covered and "enclosed " area. Think carport.

I've been using an extension cord and decided it's time to run a dedicated circuit and since it's outside it's my understanding it needs to be a gfci receptacle. Problem is it trips the instant I plug the machine into a gfci outlet. It works fine with the standard outlets but trips even before powering on the machine. I know the problem isn't on the gfci side because I've tried it on multiple outlets / circuits. I'm guessing there is a ground fault or something on the machine side of things but it works beautifully with a regular outlet.

Is this an accident waiting to happen or is it ok to run it on a regular outlet even though it's technically outdoors?

If at startup or normal run, you need to hunt it down and find out. Truant may be the switching.

Even so, GFCI outlets in general are not happy campers with machinery, indoors or out.

My C-H compressor has no faulting BUT, all-too-often kicked a GFCI breaker on SHUTDOWN off the back of a nasty BACK EMF spike, cheap-ass inbuilt contactor with no snubber.

Having investigated, proving to my own satisfaction that was all that was wrong with it, and harmless, I just used a naked outlet rather than alter the switchgear on the unit. Next go, better compressor, more money and longer years involved, I'll fix it if it needs fixed.

This one is but "kleenex class", so I cannot be bothered. You are probably in a similar situation with "marginal", not true "industrial grade" goods?
 
I think static builds up fast on any blaster. Is there a ground wire solidly attached to the metal cabinet. Is the blasting hose conductive rubber? Dos it have lights or a fan.. I am not sure why a blasting cabinet has electrical attached?
 
Try blasting with silicon carbide beads. It'll zap your teeth out, even through those heavy rubber gloves.
Try conductive hose and fittings, and a common blast nozzle grounding kit like the grownups use, and your teeth can go back to falling out more slowly from ordinary untreated Asian or Kalifornickyan debauchery, scurvy, incredible age, bar-fights, and such...

:)

Not as if you were the first-ever Virgin at it, or there weren't already threads about it "right here on PM" or a hundred or more companies selling solutions.

Here's but ONE:

BlastOne : Tips : 10 Ways to Reduce Static Build Up in Blast and Vacuum Hoses

But it sounds like his ground fault thingy trips even before he turns on the blaster, so ...

Perhaps it has an "AI" circuit?

An "Artificial Idiot" that smells trouble in advance? Or creates it?

You didn't think failed politicians went off to second careers cleaning terlets or serving up over-priced cawfee, didja? They earn big bucks at competing with "AI" as the real McCoy. Genuine not, "Artificial" Idiots. See Jimmy Carter, John Kerry, and Biden, "Sociedad Amnesiac".

:D
 
Try conductive hose and fittings, and a common blast nozzle grounding kit like the grownups use, and your teeth can go back to falling out more slowly from ordinary untreated Asian or Kalifornickyan debauchery, scurvy, incredible age, bar-fights, and such...
Cute. But no relevance to reality. You've obviously never done this. WITH a ground lead alligator clamped to the part you're blasting, WITH the blaster heavily grounded, WITH clean fresh beads, WITH heavy non-conductive gloves, WITH WITH WITH and standing on a heavy rubber mat, using silicon carbide gives an impressive miniature lightning show in the cabinet. Occasionally, no matter how careful you are, you'll catch an edge and wowee zowee, that smarts.

Does a heck of a job removing metal, too.
 
Cute. But no relevance to reality. You've obviously never done this.

*yawn*.. I'll have to have the lady in the back office check the contract, but I'm pretty sure there weren't no provision to be as careless or foolish as you. Or at least not in the same direction. So in at least THAT sense, "not quite that way!"

"Daylighting" OTOH? Well. Who here has NOT gone clear through a panel before they got the hang of what air and grit can do? Buggers didn't want 'em artistically artificially ventilated, shudda made 'em thicker.

:(

So got my OWN set of scars on the ass, thanks.

Just not from sparks and store-bought lightning bolts!

:D
 
*yawn*.. I'll have to have the lady in the back office check the contract, but I'm pretty sure there weren't no provision to be as careless or foolish as you. Or at least not in the same direction. So in at least THAT sense, "not quite that way!"
In other words, you've never run silicon carbide in a bead blaster so you have no idea what you're talking about. As usual.
 
Getting back to the OPs problem.

In the UK at least the normal "correct" solution to this sort of problem is to provide a separate feed from the utility incomer via its own "consumer unit" with appropriately rated RDC (earth leakage) and MCB (fuse equivalent) trips. Presumably you have something equivalent on your side of the pond. The actual connection to the equipment being by suitably weatherproofed connectors. Whether intrinsic or, as in my case, via a sealed box with weatherproof lid.

Something like this is normal in home or very small shop situations.

Garage Consumer Unit.jpg

It is of course not weatherproof so has to go inside. I prefer to have a separate lever isolator switch to turn the externals off rather than use the switch on the RCD which isn't really rated for 'undreds of operations. My isolator lives immediately above the door.

Clive
 
In other words, you've never run silicon carbide in a bead blaster so you have no idea what you're talking about. As usual.

Lot's of things I never done. I've never jumped out of a perfectly good aircraft, shot myself in the ass, shagged anything with hooves, nor et more than a pound of cut nails for lunch as an "Iron Supplement" at one go, either.

Poor prep and careless working doesn't make you "wise". "Wise" is the guy who laughed his ass off when you lighted up yer dentures and was careful to NOT repeat that sound and light show.

Prolly a Chinese on yer own staff, too, so he didn't even bat an eye until AFTER work regaling his mates over a shared "Snow beer" with tales of the pet Gweilo's latest dumb stunt.
 
To the OP...I have had issues with GFI receptacles in the past similar to what you are experiencing. You might solve the problem by removing the motor and baking out any moisture in it, or not. I realize you are in an area where there are many lurking dangers, so take my suggestion with a grain of salt. If this is going to be outside then drive a dedicated copper alloy ground rod into the most moist place near the cabinet. Run a piece of #10 solid copper to the cabinet and make sure everything on or around the unit is grounded to that. Use appropriate hardware and techniques ( clean paint from grounding point, use star washers etc.)If something shorts out and blows the breaker then fine...at least it didn't kill you.
 
I want to know, just thinking how the hell did any of us get to say a ripe old age if 15? Let alone hyway speed limit growing up at a time when very little was grounded properly.
We had 2 conductors on 120 volt items. Then someone was standing in water got a little shock called the we cheated and steel law firm and well here we are today ( if it killed them they just got buried). No such thing as just be smart about it. Ground faults are a pita in the shop environment. The op is using 120 volt equipment if it is grounded correctly he probably won’t ever have a problem. Only the one hooking it up, the cord all the way to and including the panel can be sure of that. Probably is the chineseium motor causing the issue


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I want to know, just thinking how the hell did any of us get to say a ripe old age if 15? Let alone hyway speed limit growing up at a time when very little was grounded properly.
We had 2 conductors on 120 volt items. Then someone was standing in water got a little shock called the we cheated and steel law firm and well here we are today ( if it killed them they just got buried). No such thing as just be smart about it. Ground faults are a pita in the shop environment. The op is using 120 volt equipment if it is grounded correctly he probably won’t ever have a problem. Only the one hooking it up, the cord all the way to and including the panel can be sure of that. Probably is the chineseium motor causing the issue


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Right, a tripping GFCI, absent a defective GFCI, means one thing, there is current flowing that is not coming out the neutral.

Granted wearing rubber shoes solves most issues, but the neighbors 6 year old pads over and touches the case when it is off and gets killed, your argument will sound even more ignorant




I would get a meter and start looking. Since it trips when off there is not that much to check.

I am wondering if the internal wiring of the blaster is swapped somewhere, if the neutral is being switched instead of power......dunno



All my exterior outlets are GFCI and nothing I plugged in trips them, not even some raggedy ass extension cords
 
If it trips when first plugged in (assuming nothing runs until you flip a switch) there must be leakage somewhere.

Are there any line-to-ground capacitors?

In order to diagnose something like this you first need to know exactly what your electrical bits look like. The small current that will trip a GFCI usually isn't a hazard UNLESS it finds a good path through your body. If so it is definitely enough to stop your heart, which is why these devices exist. I can tell you how to check for leakage, but first ...

DISCLAIMER

The following described test is potentially dangerous and should only be performed by personnel with a good understanding of electrical safety. During the test the electrical safety ground will be temporarily disconnected while measurements are taken. THE GROUND MUST BE RECONNECTED BEFORE TOUCHING ANYTHING!​

3.5 milliamps (mA) of leakage current is the trip point for 120v circuits. This current flows down the ground wire so it must be interrupted in order to take a measurement.

If you have a good meter that can accurately read low mA you can just connect it between the ground of the equipment and the extension cord. THE CORD MUST BE UNPLUGGED WHILE CONNECTING!

If you only have a cheap meter you can make a special test cord. In this cord, WHICH IS ONLY USED TEMPORARILY FOR THIS TEST, the ground lead is cut and a 1500 ohm resistor in parallel with 0.15 microfarads is inserted in the ground lead. There must also be provision to connect a voltmeter to each end of the resistor.

The formula for leakage current using this is

Current (in mA) = ac voltage on meter divided by 1500​

5.25 volts ac would be .0035 amperes or 3.5 milliamperes, which is the trip point.

Diagnosing is tedious because it requires a separate test before and after everything you disconnect, WITH THE CORD UNPLUGGED AFTER EVERY TEST BEFORE TOUCHING ANYTHING!

If you are sure you are disciplined enough to do that this will isolate the problem to the device or component causing the GFCI to trip. After you have isolated that make another post with details and members should be able to help with the next step.

I'm not being a dick with all the bold text warnings. If there is a fault it could be lethal to touch it while the sand blaster is ungrounded. Normally the non-GFCI outlet is shunting this excess current to ground.
 
I wonder.....I wonder if the blasting cabinet has swapped hot for neutral
somewhere.

Nope. GFI interrupters only measure the *difference* between hot and neutral currents. They don't
care about which is which.

Likewise all the nonsense advice about grounding inside the cabinet. or type of blast media. The thing
trips BEFORE HE TURNS IT ON.

This isn't building a quantum computer. Unplug the cabinet. Measure between each power lead (flat blade) and the ground on
the plug at the end of the cord, using a good DVM that reads to 20 megohms. Report back the results. Two numbers please.
 
What machine is this that trips the breaker? Does it have anything to do with the bead blaster? Is it an electric or gas engine compressor? Maybe there is metal dust on the outlet of the GFCI.
Bil lD
 








 
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