hoist trips GFI

[Davebones]

We have a small hoist that is on the roof . Just below the hoist is a outlet that it is plugged into . It occasionally will trip the GFI below that the outlet is fed from . This is on a separate circuit . Can't find no moisture or anything else that could cause the GFI to trip . It's intermittent . Have also replaced the GFI . This is a permant installation installed a few years ago . Since its a outlet its plugged into we understand it has to be GFI protected . Is there any reason we can't hard wire this in and eliminate the GFI ???

 

[iwire]

The first reason not to eliminate the GFCI is because it is likely doing exactly what it is supposed to be doing. Protecting personal from faulty equipment.

The second reason not to hardwire it would be because it is very likely not listed for hardwiring. If you where to hardwire you would have to install a disconnect switch.


I know you said you did not see any moisture but it could be condensation inside the motor itself. Is it exposed to sun and then cool nights?

 

[kwired]

When is it tripping? If it is tripping right when you shut hoist off (either direction) it is likely an inductive kick back issue.

 

[iwire]

When is it tripping? If it is tripping right when you shut hoist off (either direction) it is likely an inductive kick back issue.

So what is your solution for this?

I find it unlikely that it operated for a number of years and suddenly it starts kicking back.

 

[kwired]

So what is your solution for this?

I find it unlikely that it operated for a number of years and suddenly it starts kicking back.

I guess we don't know how long it has been there or how often it is used. If used a lot with no troubles and suddenly is tripping - then there probably is a ground fault issue.

My thoughts were maybe skewed a little by a hoist I have dealt with that is only used when maintenance requires heavy items lifted up/lowered from a structure. It may go for a couple years without ever being used at times. But seems like whenever it is needed something doesn't work on it. I can also see it having a high inductive kickback, though on this one it never does trip the GFCI (for that apparent reason anyway).

 

[JFletcher]

Look for damage on the hoist cords, especially near strain reliefs; it may not even be visible. Did a fryer basket hoist at a peanut packing plant a few months back; found the strain relief missing where the cord went into the motor housing, resulting in a short, as well as an intermittent fault in the same cable where excess had been tied to a railing. as iwire wrote, you have a fault, just a matter of tracking it down.

 

[growler]

The second reason not to hardwire it would be because it is very likely not listed for hardwiring. If you where to hardwire you would have to install a disconnect switch.

I would check with the manufacturer to see if it's listed for hard wring. If it's commercial equipment it may be listed for hard wiring like a commercial garage door opener.

More information would be needed before makeing a decision.

 

[Davebones]

Yes it is exposed to the weather . A outside contractor installed it a few years ago . Welded the frame to building steel . Only used occasionally .

 

[Davebones]

Went thru everything on the hoist . Never looked at it but it's actually a boat hoist so it's designed for outside . Found a capacitor on the side had water in it . That's what was tripping GFI . Thank everyone for the suggestions

 

[steve66]

Went thru everything on the hoist . Never looked at it but it's actually a boat hoist so it's designed for outside . Found a capacitor on the side had water in it . That's what was tripping GFI . Thank everyone for the suggestions

I'm too late. I was just about to ask if it was a capacitor start motor.

It may be oil leaking out of the cap. instead of water leaking into the cap.

I'm not exactly sure why that causes GFCI's to trip, but I believe it does. The oil is supposed to be a dielectric oil. Sure, I can see it having enough current leakage to trip a GFCI, but if that's the case, why don't they ever trip until the capacitor starts leaking??

 

[iwire]

I would check with the manufacturer to see if it's listed for hard wring. If it's commercial equipment it may be listed for hard wiring like a commercial garage door opener.

More information would be needed before makeing a decision.

You are right, it could be listed for that but then there is still the issue of it becoming a shock hazard if the EGC fails. Obviously at times the unit is faulting to ground.

I would not go that route.

 

[iwire]

<soap box moment here>


It blows my mind that the same electricians that would never consider raising, changing or removing the OCP for a load that keeps tripping think nothing of pulling out a tripping GFCI.

The tripping GFCI is as much of a sign of danger as a tripping breaker.

<steps down from soap box>

 

[K8MHZ]

<soap box moment here>


It blows my mind that the same electricians that would never consider raising, changing or removing the OCP for a load that keeps tripping think nothing of pulling out a tripping GFCI.

The tripping GFCI is as much of a sign of danger as a tripping breaker.

<steps down from soap box>

A capacitor with water on it presents danger?

I am not saying the GFCI should have been removed. I am just wondering what danger was present with the OP's lift. I grant you that there was a defect and the GFCI 'discovered' it, but was that defect a hazard or just a nuisance?

I don't see a tripping GFCI to be nearly as much of a sign of danger as a tripping breaker. A sign of danger, yes, but not to the extent of an OCPD tripping.

FWIW, I am in your court about not getting rid of the GFCI, it would stay, the offending load would go or get repaired. I was just wondering how a wet cap could present a hazard to a person.

 

[iwire]

A capacitor with water on it presents danger?

If it is faulting to ground enough to trip a GFCI it absolutely presents a danger if the EGC becomes compromised.

It does not mater what the source of the ground fault is, capacitor, winding etc.

I grant you that there was a defect and the GFCI 'discovered' it, but was that defect a hazard or just a nuisance?

I would call an engized chain from a hoist as a hazard not a nuisance.

I don't see a tripping GFCI to be nearly as much of a sign of danger as a tripping breaker. A sign of danger, yes, but not to the extent of an OCPD tripping.

I entirely disagree, the dangers are different but either can result in death. One by electrocution one by smoke or flames.

 

[growler]

You are right, it could be listed for that but then there is still the issue of it becoming a shock hazard if the EGC fails. Obviously at times the unit is faulting to ground.

It blows my mind that the same electricians that would never consider raising, changing or removing the OCP for a load that keeps tripping think nothing of pulling out a tripping GFCI.

If GFCI protection is required is obvious that you wouldn't remove the GFCI protection.

"But" if GFCI protection is not required then the motor is still grounded and safe.

I'm sure there are electric motors all over the place that were not intended to run on GFCI protected circuits. They are not ment to be hand held with a chance the ground would come loose. Hard wired and grounded are as safe as your water heater, dyer, range, A/C condensor, air handler, most older garbage disposals ( older ones not on GFCI).

How many motors do you touch all the time that are not GFCI protected ? You don't have any idea if there is enough current to ground to trip a GFCI but you know it's not enough to trip a breaker.

PS. The world is over populated and we all have to go sometime.

 

[iwire]

"But" if GFCI protection is not required then the motor is still grounded and safe.

Until it is not grounded and then you get a shock while working a hoist on a roof.

I would not remove the GFCI.

How many motors do you touch all the time that are not GFCI protected ? You don't have any idea if there is enough current to ground to trip a GFCI but you know it's not enough to trip a breaker.

That is correct I usually don't know if a motor has a fault. I worked on four 500 HP motor that each one was flowing over 15 amps on the EGC and surly would kill you if the EGC was broken. The unsafe conditions were fixed.

In this case we do know the motor has a fault and for that reason I would not remove the GFCI.

PS. The world is over populated and we all have to go sometime.

No doubt, but I am too much of a wuss to help people out the door.

 

[K8MHZ]

If it is faulting to ground enough to trip a GFCI it absolutely presents a danger if the EGC becomes compromised.

It does not mater what the source of the ground fault is, capacitor, winding etc.

Sure, but I don't understand how a cap with water in it can become a ground fault. I might if I saw how it was mounted, but I am just wondering, that's all.

I would call an energized chain from a hoist as a hazard not a nuisance.

Where did you see 'energized chain?'

I entirely disagree, the dangers are different but either can result in death. One by electrocution one by smoke or flames.

I guess the two really aren't quantifiable. As you pointed out, there are some electricians that think nothing of not using a GFCI vs. not using an OCPD.

However, in the real world, what would you sooner be without, a GFCI or an OCPD? Would you refuse to work on a live circuit that the OCPD bypassed? I sure would, the thought of that sounds hideous. Would you refuse to work on a live circuit that had proper OCPDs in place, but had no code required GFCI? I'll bet you have done it a bazillion times. If you haven't, you are a lot younger than you look. Just kidding. But to me no OCPD means arc flash, big boom, wires on fire and the like with just one touch of two wires. No GFCI means a poke if I slip up. Those are just mental conjurings, of course. The worst case scenario of both is death, but the GFCI won't keep the circuit from erupting in flames.

They are wonderful devices, I am aware of that. I still don't see how water on a capacitor can create a hazardous fault to ground.

 

[iwire]

Sure, but I don't understand how a cap with water in it can become a ground fault. I might if I saw how it was mounted, but I am just wondering, that's all

I have been talking about ground faults in general regardless of the source. Someone else mention it could be the cap. I have no reason to think that could not be the cause but I really don't know.

Where did you see 'energized chain?'

I did not see it, I said it. . That could easily be the result of a ground fault in a hoist that becomes ungrounded.

I don't always install GFCIs, as a rule I install new equipment that I assume is safe and I count on the EGC to remain intact. It will take two problems for it to become energized, a ground fault and a broken GFCI.

On the other hand I never remove GFCI required or not from equipment that I have been called to because the GFCI is tripping. That tripping is telling us we have already met one of the conditions needed to energize the equipment. Now we are actually using the EGC as a current carrying conductor. Things will be fine until someone or something opens that EGC.

I am not telling anyone they should go around installing GFCIs everywhere, I don't either. I am only saying how I look at it and how I do things.

However, in the real world, what would you sooner be without, a GFCI or an OCPD? Would you refuse to work on a live circuit that the OCPD bypassed?

As far as working on it live I would prefer a GFCI.

A shock is a shock.

But to me no OCPD means arc flash, big boom, wires on fire and the like with just one touch of two wires.

The arc flash is the same, the boom is the same, wires only on fire if they become welded together.

 

[kwired]

Sure, but I don't understand how a cap with water in it can become a ground fault. I might if I saw how it was mounted, but I am just wondering, that's all.

I think what was found in OP's application was likely the capacitor housing was filled with water, and therefore a fault to ground from conductors attached to capacitor through the water to the capacitor housing/motor housing which both are likely bonded to the EGC.

Depending on capacitor location and motor orientation, water can accumulate in such space - even water that originates from condensation within the motor.