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Don and Barb · 09-23-2014, 11:47 AM

Quote:

Originally Posted by RV Wizard

Restudy electrical wiring 101 and the NEC. GFCI circuits do work in the RV industry when the unit and source it is plugged into are wired correctly. I have helped many folks find bad heating elements in their ref. and water heaters that will trip GFCI circuits. Hot skin is a separate issue but again is a result of bad wiring.

I have 2 outlets that don't work in my dining area. I have replaced the only fuse that was blown, but when I turn the power back on I get a loud high frequency noise (sounds like an alarm) and the fuse blows again. This last weekend I noticed that the outlets are GFCI's but with no reset/test button. In fact, I have these on all outlets and the only one with a reset/test button is in the bathroom. Are these supposed to reset automatically? The fuse blows so fast I don't have time to locate where the sound is coming from, or to test these outlets. Any ideas?

TQ60 · 09-23-2014, 12:05 PM

High frequency noise sounds like an inverter or other switching supply.

Possible small inverter added someplace.

Wire a light bulb up to use as fuse then you can see the glow of bulb as current indicator.

Then flip switches or unplug things until bulb goes dim.

BFlinn181 · 09-23-2014, 12:08 PM

First, you have a fuse that protects your 120 v AC wiring? Do you mean circuit breaker? It's not uncommon for outlets to be daisy chained through a GFI protected outlet. Those outlets then often have a sticker announcing they are GFI protected. GFI outlets do not automatically reset, they must be manually reset. Try turning off your circuit breakers, then reset the GFI. Turn on circuit breakers one at a time until you hear the noise or trip the GFI. This will eliminate other sources of the noise. If it is the GFI,then you could remove the GFI from the wall or cabinet and disconnect the wires 'down stream.' Then reset the GFI and see if it still trips or makes a noise. It could be a bad GFI that needs replacement.

wa8yxm · 09-23-2014, 02:28 PM

IF an outlet says GFCI but has no button.. There are two possible legal situtations (Out of 3 total)
1: The button is on another outlet, OFTEN but not always in the bathroom.
(Mine is in the half bath)
2: The button is in fact a combination GFCI-Circuit breaker

And the illegal one: False label no GFCI.

One more thought comes to mine.. The O/P titled this thread GFCI PLUGS.... Though such devices do in fact exist, I have one in fact (On my Deceased wife's hair dryer)

Those are outlets son, OUTLETS, not plugs, plugs is what goes into 'em.

Don and Barb · 10-03-2014, 01:38 PM

Quote:

Originally Posted by TQ60

High frequency noise sounds like an inverter or other switching supply.

Possible small inverter added someplace.

Wire a light bulb up to use as fuse then you can see the glow of bulb as current indicator.

Then flip switches or unplug things until bulb goes dim.

The high freq sound, maybe I should have said pitched sound, it's like a smoke detector alarm. My smoke/fire/carbon monoxide alarms are battery powered, not wired in. I have one alarm, not sure what it is, but it has an LED on it and shows that it's working. As for the GFI outlets, all of them work, 5-6 of them, except for the 2 I mentioned which tells me they are not on the same circuit as the bathroom GFI that has the reset button. Anyway, thank all of you for your suggestions, I'll let you know if I ever figure this out.

TQ60 · 10-03-2014, 08:06 PM

Okay...

Start over...

High pitched smoke alarm like noise from someplace and 120 volt circuits bad?

Noise first.
Can you touch the device making the noise?

No...could be something under dash or panel like low air or jacks not up.

Will need to locate device making noise then either trace wires or labels or maybe pull fuses until it stops and see what else is on the fuse or if lucky labeled.

For 120 vac the dead ones could be bad or open breaker or bad connection or defective ats.

You may need to check connections with ohmmeter and it may be difficult.

First check for continuity between safety ground round pin and neutral fat blade.

They should show as shorted together if shore line plugged in.

Next check from same point best use round safety ground between outlets as these usually are good.

Check next fat blade then confirm inverter off and shore disconnected and then check hots.

You may find either neutral or hot not connected between 2 that other wires good.

Pull the outlets with odd connection and check for bad connections.

If this does not work you may need to check from ac load center to each outlet.

These are a pain to find but really simple if you take your time and take steps like disconnecting wires at common points like white wires at buss bar.

Make a map and take notes.

You will learn how everything is wired then the issue when found will be something real stupid like a bad wire nut.

RV Wizard · 10-04-2014, 03:40 AM

Your LP detector should be hardwired in and can make this dulled high pitch squeal.

toolster · 10-04-2014, 05:23 AM

I have a gizmo that you can plug into a 20amp and 30amp to get a 50amp connection, but it will not work if the circuit has a GFCI. can anyone tell me why ?

Spk64 · 10-04-2014, 08:36 AM

I am guessing you have a ground problem with the gizmo.
Btw 20 amp + 30 amp from a pedestal is not the same as a 50 amp connection.
True 50 amp is 2 120 volt circuits at 50 amps each or 12,000 watts.
20 amp = 20 amps on a single 120 volt circuit or 2,400 watts
30 amp = 30 amps on a single120 volt circuit or 3,600 watts
I believe pedestals share the 20 and 30 amp feed so may realistically not see the combined 6,000 watts.

docj · 10-04-2014, 09:03 AM

Quote:

Originally Posted by toolster

I have a gizmo that you can plug into a 20amp and 30amp to get a 50amp connection, but it will not work if the circuit has a GFCI. can anyone tell me why ?

Contrary to the other response to your question, you don't have a problem with your "cheater box" (that's what most people call your "gizmo"). Cheater's won't work with GFCI circuits probably because they alter the current flow through the neutral conductor. GFCI's work by comparing the current flow on the hot and neutral conductors. If they don't balance very precisely that is evidence of a current leak. The cheater joins the two hot and neutral conductors so the current on each leg no longer looks balanced.

Skip426 · 10-04-2014, 09:20 AM

Quote:

Originally Posted by toolster

I have a gizmo that you can plug into a 20amp and 30amp to get a 50amp connection, but it will not work if the circuit has a GFCI. can anyone tell me why ?

Does the gizmo , trip the GFIC , as soon as it's plugged in or after the coach is plugged to the gizmo.
75% of RV's will trip a GFIC circuit, my first 3 RV's would operate plugged into GFICs, last 2 wont.

Playtime III · 10-04-2014, 09:46 AM

Not an electrician, but slept in a Holiday Inn a couple of times before getting the RV...still confused. On shore power there is a ground lead to the CG pedestal.

When driving, I can have either the genny or the inverter supply AC and yet there is no earth ground as the tires block the path.

wa8yxm · 10-04-2014, 09:48 AM

Quote:

Originally Posted by toolster

I have a gizmo that you can plug into a 20amp and 30amp to get a 50amp connection, but it will not work if the circuit has a GFCI. can anyone tell me why ?

Well if you had read any of my many posts on this Chater box type Gizmo.. You would not have bought it.

The GFCI is a teeter totter, or of you like Beam Balance, (Rember those, the scales of justice type things)

It Weighs the current in the black and white wires and if there is any imbalance or if it senses any other path to ground/neutral, it trips

In the cheater box the two neutrals are connected together, so it sees a Foreign bround (Since neutral and ground are bonded at either the pedestal or the distribution panel).

And if you could figure out a way to separate them ..... Well then the current would be unbalanced and that would trip it.

So the the Cheater box "Gizmo" is a GFCI tester, if it does not trip them, then the GFCI is bad.

There is a solution, and I have posted it as well. basically it is this...

On one of the air conditioners (usually the rear) you basically cut the power line feeding it, Install a plug and socket so you convert that A/C into a plug in model, (Plugging it in to the wire that originally powered it when on 50 amps)

When on 30 amps you unplug it and using a 12ga Extension cord,, Plug into the 20 amp outlet on the box.

This puts the 2nd A/C on it's own circuit, it will be balanced so it wont trip the GFCI.

I also (in one park) put my converter on the 2nd outlet (Which is a 30 amp breakered socket there) but if I manage to take the batteries down to the point where the PDI 9180 + wizard goes into BOOST MODE... Will trip it.

Gary RVRoamer · 10-04-2014, 11:30 AM

Quote:

I have a gizmo that you can plug into a 20amp and 30amp to get a 50amp connection, but it will not work if the circuit has a GFCI. can anyone tell me why ?

GFCI works by very precisely comparing the current flow in the hot and neutral wires. The GFCI trips because there are two neutral wires in use and the current from each hot wire does not return exclusively via the neutral that is paired with it. This the GFCI on each outlet sees an unbalanced current flow and thinks there is a short somewhere. There isn't in this case, but it can't tell the difference.

Quote:

When driving, I can have either the genny or the inverter supply AC and yet there is no earth ground as the tires block the path.

The generator or the inverter provides the ground path when they are in use. Each has its own "ground", even though it is not an earth ground. The "earth" in this case is the RV chassis that is connected to generator and inverter both via a ground strap (wire).