Surge Current Tripping of GFCI

"nuisance tripping" sometimes occur,you should investigate

Yes. will trip if start up current is more than rated for more duration than

I²t of GFCI.

Pardon me, but i think Ground Fault Circuit Interruptor (GFCI) is the American term for what is RCCB in the IEC countries, so i believe it will trip ONLY on earth leakage/fault. Not on any kind of overcurrent, even short-circuit on line and neutral (or line-line in multiphase applications)

Check this link: http://www.elec-toolbox.com/Safety/safety.htm#GFCIs

Most GFIC have current measuring (over load & short circuit) shunts built-in.

i am still perplexed. The webpage talks only about personnel safety (_{A groundfault circuit interrupter (GFCI) is an electrical device which protects personnel by detecting potentially hazardous ground faults and quickly disconnecting power from the circuit. A potentially dangerous ground fault is any amount of current above the level that may deliver a dangerous shock. Any current over 8 mA is considered potentially dangerous depending on the path the current takes, the amount of time exposed to the shock, and the physical condition of the person receiving the shock}).

The diagram shows something similar to a CBCT, the direction of currents shown implies cancellation of go- and return-currents under normal conditions. Only when there is a leakage to earth the currents don't cancel, and the residual current trips the RCCB.

RCBO is another story. Its primary function was still (till 2004 at least) to protect people against shocks. The secondary function was to trip on overload and short-circuit, which was being eminently done by MCB anyway.

The GE GFCI which is an RCBO is a new one on me, thanks SHAMITHGAMBHIR1

Correct, the primary function is to prevent electric shock. Over load & short circuit is additional advantages.

That's great input ... thanks. GA.

Why not the government or manufacturer or testing authority ensure good quality items only are sold in its territory. if UN not willing to do it. like WHO,ILO.FAO etc. Can UN lay down standards to be maintained?.

Nowadays GFCI includes providing the protection of standard circuit breakers. it is like RCBO. i had used GE GFCI which provided ground fault,oc, sc protection.

GE GFCI

http://www.geindustrial.com/publibrary/checkout/Brochures|DEA-235|PDF

for catalog ref.

GE GFCI CATALOGUE

It depends upon the device. "GFCI" is not a suffcient description to describe its operation exactly.

If it is a residual current breaker with overload, as implied by the "15 or 20 amp" in the original posting, then it certainly will trip if the current drawn exceeds its overload trip rating, even if there were no imbalance current at that time. It will then have a second rating, being the imbalance current that, for domestic devices, will be typically 30mA; if the imbalance exceeds this value, then it will trip on this as well.

Exactly what it is cannot be seen from here.

This is the problem.

A Xerox Laser printer is plugged into a home 15 AMP basic GFCI that has no visible current limiting feature. After printer is turned for about 15 seconds the printer starts the final phase of start up and the GFCI trips. I may have incorrectly assumed that there is a start up current that is tripping GFCI.

I plan to install a 20 AMP GFCI. If this unit trips the answer will be that the printer has as a ground fault current leakage in the final phase of the start up sequence.

Thanks for all of your comments.

Er...a printer taking >15A from the mains? Even @110V, looks rather high to me....does the nameplate specify that kind of amps? A heavy duty printer if so, obviously.

If it is your own money, i would suggest you first find a way to see if you have an earth leakage which comes in when some diagnostic circuit kicks in, before you spend money on a bigger GFCI. i am something of a designer of switchgear, and i would squirm if one of my designs nuisance-tripped on a surge. i design them to take such surges in their stride....

NO!!!!!

Never replace a circuit breaker with a higher amperage breaker without verifying the quality and size of the wires used on that circuit. The 15A breaker you have is (presumably) the proper rating for the house/building wiring you presently have.

Your latest reply though does beg this question: why in the world do you have a printer attached to a GFCI protected outlet? Do you need your prints in the shower?

The markets are acting very flaky lately but how can the sale of 15, 20 or even a 1000 Marshall Amps affect the Global Financial Center Index?

_{Just having a little acronym abuse fun.}

There was no choice in using the circuit with the GFCI since the room outlets were connected to the Kitchen GFCI. I have no idea why this was done. We did not build the house.

The solution will be to have a dedicated outlet installed in the room that has the printer. It appears that the printer uses 3 amps (approx 360 watts running and possibly 9 amps (approx 1080 Watts peak).

We were just advised by the Xerox repair person that all these printers trip GFCI's.

I'm amazed that this is true since all the electrical equipment that we built and sold was hipot tested for current leakage.

Thanks again for all the input.

Who is certifying items like printers, is it UL,NEMA...?. Why don't they incorporate a filter to prevent tripping?. Why not the government create a testing agency for items manufactured/imported?. If a person or property get electrocuted or burns who will take responsibility?. If a person dies will money from insurance replace him?. I have heard some storage water heaters tripping too. In BS ring circuit type of wiring, many outlets are connected to a single RCD(gfci)/MCB in the load centre/CU thereby tripping all outlets in that circuit if connected appliance in any one of the outlets develops a leak,in which case it will be prudent if all outlets incorporate leakage trip facility.

The room outlets were connected to the kitchen because it was easier/cheaper than running the wire back to the breaker box, and because they could get away with it. Depending on how old the house is, it may have been built when there were few appliances ever plugged in. They may have felt that the person using electricity in the kitchen would be the person running the vacuum in the den, and never at the same time. It would be overkill to run every outlet back to the breaker box on it's own breaker.

I would run the new circuit and be done with it.

Somehow your printer is producing a high enough leakage current that falsely tripping the GFCI, or your wiring terminations are not properly polarized? Eitherway, by using an Isolation Transformer 1:1 with the proper VA rating should solve your problem.

If the room outlets are "down streamed" from the kitchen outlet, simply rewire the kitchen outlet so the supply to the other outlets are on the supply side of the GFI. If there are outlets that need to be GFI protected, add GFIs at those locations. If the panel has a GFI breaker, replace it with a standard breaker and add GFI receptilcals where needed. -- JHF