OT---Generator GFCI

I have a Coleman 5K watt gas generator. I frequently use it for 115V supply with it in the back of my truck. Is there any reason why I should not replace the 115V outlet with a GFCI?
I just like the added safety..

Unless your truck is strap grounded to the genset, and the truck is attached to a substantial earth ground, The GFCI might not reliably detect lost current to you. It probably depends on the type of device being installed. The genset is also prone to modest spikes and stray voltage issues that are OK for its purpose, but not ideal for a sensitive GFCI device. Current surges, Inductive loads, and flourescent light ballasts being switched on and off will trip GFCI systems in a home. I imagine it would be a constant battle to keep it operational. Using three prong 120, or appropriately grounded 3 phase and 220 sigle phase appliances should be sufficient. Jim

I think a lot of single-phase 120-v residential GFCI's are designed to trip under either of two conditions;
First, if there are several milliamps of ground current going down the ground wire.
Second, if there is a difference of several millamps of current between the currents flowing in the hot wire compared with the neutral wire.

I made a short extension cord with a GFCI box added to the end. That way, I have protection. However like mentioned below, GFCI's will trip when there is a difference in any current, ground or neutral. Some GFCI's will trip sooner than others too. Try making an extension cord and see what happens.

Is a GFCI even needed on a generator? A generator in the back of a truck isn't connected to ground, the earth. Therefore the output is ungrounded. This means you shouldn't get shocked unless you touch both neutral and power at the same time.

You could test this idea by using a neon test light. Put one side of the tester in the power side of the plug-in and hold on to the other side. My bet is the test light won't work.

Try it and post back.

Actually to expand a bit, a torroidal core surrounds the HOT and NEUTRAL. If all the curent flowing out the hot is returned by the neutral theres no voltage induced into the coil so no trip HOWEVER if ANY of the current flowing out the hot is getting returned elsewhere (an equipment grounding conductor,,,,,,,,,,or your body via its contact with mother earth,,,,,,,,,,,or your body via its contact with the neutral,,,,,,,,,or the hot is in contact with a grounded metal case of a tool BASICALLY ANYWHERE BUTTTTTTTTTTTTTT THE NEUTRAL) theres a current imbalance and voltage is induced into the coil making the GFCI trip.

Its not really like two conditions, ITS ANY CONDITION whereby the Neutral current does NOT equal the hot line current and it only takes like 5 millimaps of difference to induce sufficient voltage into the torroidal coil to trip the breaker.

Hope this helps

John T

Jiles, you say you like added safety as do I, its just a question of balancing potential nuisance tripping verus that added safety.

Theres some old wives tales about GFCI's I will try to explain and debunk.

1) YES they will still work on your portable genset regardless if its Neutral is bonded to mother earth or the gennys metal frame or the truck frame or the neutral isnt bonded to anything else

2) If theres a 5 millimap difference in the current going out the hot versus whats being returned by the neutral THE GFCI WILL TRIP and thats so regardless if the gennys Neutral is attached to earth or the gennys frame or the pickup truck frame or nowhere

3) On portable gensets with on board atatched receptacles used to power plug n cord conencted (to the genset) tools, ITS NOT REQUIRED TO BOND THE NEUTRAL TO MOTHER EARTH. The Neutral IS BONDED however to the gennys metal case/frame.

4) Another technical consideration. If the gensets case/frame is NOT in contact with mother earth and you come between earth (your feet DUH) and a live hot conductor (say your hand gets on a hot wire) YOU TECHNICALLY SHOULDNT GET SHOCKED IN THE FIRST PLACE as voltage is between Hot and Neutral NOT Hot and Mother earth buttttttttttt theres capacitance etc so you could still feel a tingle but it shouldnt be life threatening as it takes something like 50 milliamps thru the ticker for defib BUT NO WARRANTY THIS IS THEORY IM NOT RECOMMENDING IT LOL

5) The way they work is a Torroidal coil surrounds the Hot and Neutral conductors and if the current is the same in both no voltage is induced into teh coil trippign teh GFCI HOWEVER Id theres 5 milliamps less flowing back then the hot is supplying (leakage current maybe via your body or earth or a short etc etc ANYWHERE but Neutral) voltage is unduced and she trips

SUMMARY

SOOOOOOOOO THERES NO HARM IN USING ONE,,,,,,,,,,YES IT CAN BE SAFER (given certain circumstances), BUTTTTTTTTTTTT IF SHE NUISANCE TRIPS CONSTANTLY IS IT WORTH IT??????????????????????

John T Longggggggg retired EE

Youre right in strict theory with no capacitance or inductive effects, it shouldnt light because theres no voltage between the hot and mother earth, see my post above. fun discussion for us sparkies at least lol

John T

(quoted from post at 23:47:09 09/05/11) Youre right in strict theory with no capacitance or inductive effects, it shouldnt light because theres no voltage between the hot and mother earth, see my post above. fun discussion for us sparkies at least lol

John T

Click to expand...

John T---Here's some more fun --LOL--My son was just given a similar generator that would not run. It has set for a few years and the wiring was "Botched up"
I just finished getting the motor running again and worked on the generator for a short time.
Here is the problem--
There are four wires exiting the generator--Black--Red--Orange--and Green.
Black to Orange= 120V
Black to Red=102V
Red to Orange=20V
Strange thing is, I installed a new 120V recepticle and hooked the Black wire to Neutral and the Orange (120V) to Hot I also hooked the Green to Ground.---It would not even run a 120V drill???????
Changed the Orange to Red (102V) and the drill worked fine.
We checked operation with Three different electric motors.
Any thoughts or suggestions??

Ground ?

You can trip a GFCI by touching neutral wire of a GFCI to the ground wire. Just try it. Short a wire from ground to neutral in the GFCI.

I have a special GFCI with a spike protector. It trips every time there is a lightning strike near my house. So Yes, current in the ground wire can trip a GFCI.

It isn't the current in the ground wire. It's the reduction of current in the neutral as the ground carries current. Of course the gfi trips when the neutral and line are no longer balanced.

My son removed a GFI that had smoked during a lightning strike.I opened it and found 2 transistors blown apart.Many other small parts that could fail.Found some that wouldnt trip on test and one that wouldnt trip on an old metal drill motor that had leakage.Dont bet your life on a GFI.People found they cant use a fence charger on GFI.GFI s have points that can weld.I like stoves that have a label that says hot when in use,Gun barrels that say Warning, misuse can cause injury or death.

Long time ago, maybe seventies, when these th ings first come out; I would tell customer this will protect you in your swim pool. They always said prove it. I would stick my finger on little screwdriver and insert into hot side. surprise, I alwaYS GOT SHOCKED. Had to quit doing that. Maybe I should try again. OUCH
Untitled URL Link