WFCO Converter tripping house GFCI?

[FairviewFairyFarm]

Hello everyone! My TM has been tripping the 15amp GFCI in my garage and I have traced it to the converter breaker on the 120v side of the WFCO 8955 panel. When I plug into nongfci outlet, the DC reads at 13.4v, which makes me think the converter/charger must be working somewhat correctly? What could be causing that GFCI outlet to trip, but everything seems to function normally when plugged into standard outlet? We are embarking on a trip soon and don't want any issues on the road! Thanks for all the info, this forum rocks!

[commodor47]

One possibility is a burnt out heating element in the water heater. The test is to remove both wires attached to the heating element, protect them either with wire nuts or electrical tape, then plug back into the outlet with the tripping GFI. If that solves the issue, you should replace the heating element. There are several posts on testing the heating element and a detailed explanation of how to replace it in this thread:

http://www.trailmanorowners.com/foru...ad.php?t=11489

The first post in this thread is a good example of the way to test for a bad heating element:

http://www.trailmanorowners.com/foru...heater+element

Let us know how you make out.

Dick

[FairviewFairyFarm]

Hey Dick, thanks for the reply, I should have mentioned that this is gas fired water heater only. We are newbies but we have isolated the problem to something on the 120v converter circuit. Does anyone know, would a ground fault on 12v side of the panel trip the 120v house gfci?

[Shane826]

You're sure the water heater is gas only? They've been gas/electric forever.

[B_and_D]

Our 1997 hot water heater is gas only, but by 2006 I believe they were putting in gas/electric.

[rickst29]

Yes, the 2006 models had gas/electric water heaters. But, a burnt out element is extremely unlikely to "fault" 1120V hot to the frame - instead, it will simply not conduct electricity at all. The 'electric' power switch, being off, should also assure that it doesn't draw anything.

Instead: It's a simple fact that many Converters (definitely INCLUDING the "miserable" 2006 WFCO in the 2619, as well as the preceding Magnetek model)) do not present level and balanced current loads on the "hot" and "neutral" sides of the 120V input while generating significant amounts of 12V power. (Either to run the Fridge in 12V electric mode, or to charge the batteries.)

Under load, the transformer is being switched by control electronics, to handle the switch (on the "hot" circuit) between positive and negative portions of the waveform. (BTW, in WFCO, this creates a 60-cycle "humming" noise, separate from the fan noise. The WFCO converter is only 2-phase.) In addition to the audible hum, that switching creates ripple on the 120V circuits ("hot" and current-carrying "neutral"). And the cheap electronic control circuits create additional ripple on the input/output 120VAC source wires. These "ripple" characteristics are not balanced in time, you can see considerable voltage differences between "hot" and "current carrying neutral" on a dual trace oscilliscope (if you can get your hands on one).

The unbalanced "Ripple" is too big for most modern, sensitive GFIs to accept without creating a fault. Campground wiring is NEVER built with GCI on the 30A or 50A circuits. If you want to plug-in the WFCO at home, then you must probably create a new dedicated circuit: And you should create it as a 30A or 50A dedicated circuit, because modern NEC requires arc-fault GFIs on all of the 15A/20A circuits. (Your Local Codes might not require arc-fault yet, but they're definitely going to require GFCI.) An exception is provided for point-to-point high-amperage circuits.
- - - - -
WFCO can be used as an AC distribution unit on a GFI circuit (running the Air Conditioner, or the Water Heater, or the Fridge in 120VAC mode). But if you try to use it as a converter for charging batteries or running the Fridge in DC mode, it will blow the GFI. (But there's no sense in running fridge with 'DC mode' when you have AC available, and the WFCO is not a very good battery charger - it typically falls into "Float" mode when the battery is only 70-75% full.)
- - - - -
Your best options for charging the battery at home are: (1) Put in a new circuit; or (2) Use a completely separate and BETTER battery charge device, such as this one: https://www.amazon.com/CTEK-56-864-A.../dp/B006G14FK8 I've got one, and it does a great job.

If you buy the CTEK (and even if you don't) you'll want to replace the cylindrical "Battery Fuse" (which runs all the TM 12V battery loads through a tiny-rust-prone spring) with this convenient and problem free circuit breaker: http://www.ebay.com/itm/12V-DC-30A-C...P/291808183404. You need this because the CTEK only delivers about 4A current (2A per battery), and can't do effective charging and battery maintenance while TM "phantom loads" consume more than a third of that total. Using this circuit breaker as a "battery disconnect" eliminates the phantom loads. (With some side effects, such as losing stereo system "memorized stations" and presets.) It needs a full day or two to charge discharged batteries, but it does a fantastic job as a "maintainer".

[FairviewFairyFarm]

Thanks for all the info, so is it bad to plug it in to a standard outlet? I have read that the WFCO 8955 is the "worst power converter"of all time and many people switch out to the Boondocker or PD converter. Do you think this would be a good idea or not necessary? How would I make a charger like the one in the link you shared work on the road?

[BrucePerens]

you can see considerable voltage differences between "hot" and "current carrying neutral" on a dual trace oscilliscope (if you can get your hands on one).

I'm not sure about your theory. I would accept that high-frequency noise on the power line could flip an AFCI or dual-function breaker. I would accept that a current imbalance that somehow sends current through the ground wire would trip a GFI. I'm having a lot of problem understanding how the current flow in hot and neutral would be unbalanced in time. Electricity doesn't work that way. There has to be a current return somewhere for current to flow in hot at all, either through neutral or ground, and this all happens at close to the speed of light. There's a velocity factor due to the line impedance that means it's slower than light, but it's negligible.

I'd suspect that if you are seeing a time difference in current flow on hot and neutral, that your traces aren't synchronized. Less expensive 'scopes alternate the traces.

I'm sure that if you have a WFCO charger, that you should replace it, either by replacing the entire converter or just the charging section. There are lots of good reasons for that besides this theory.

And if something is flipping the GFI breaker, the first thing we should suspect is that current really is traveling through the safety ground, and we should really carefully eliminate that possibility before proceeding, due to the potential for safety issues.

[rickst29]

Originally Posted by FairviewFairyFarm

Thanks for all the info, so is it bad to plug it in to a standard outlet? I have read that the WFCO 8955 is the "worst power converter"of all time and many people switch out to the Boondocker or PD converter. Do you think this would be a good idea or not necessary? How would I make a charger like the one in the link you shared work on the road?

The Bondocker upgrade improves things A LOT, but it will probably still trip the CFGI if batteries are severely discharged when you plug in. You would not need or use the CTEK on road, unless you stay at other peoples' homes: All RV parks and Campgrounds are built without GFI on the RV power connection circuits, and the Boondocker (or existing WFCO) would work OK.

I strongly recommend performing the 'Boondocker' upgrade for your Trailer, as soon as you can order it and find time to open up the Trailer and do the job (at home). It takes only 30 minutes (first time), because you don't need to re-do any of the downstream "DC appliance" connections. Most of the 30 minutes will be figuring out how to follow instructions and remove the WFCO main board. Having done it once, I could now do the job in less than 5 minutes. Your three big reasons to do this are:
#1, the WFCO converter section is unreliable, and a lot more sensitive to poor-quality campground power: it's quite likely to 'blow up' when you're a thousand miles from home;
#2, the WFCO does a significantly worse job of charging and maintaining batteries. (With SLA batteries, The Boondocker can reach 80% State-Of-Charge, while the WFCO leaves them around 70%.)
#3, the WFCO is *A LOT* more noisy on it's DC output. The presence of batteries to "filter" the noise is critical with both units, but there's a lot less noise with the Boondocker. (The switching controls are better, and the DC filter capacitors are bigger.) If you use finicky electronics on 12VDC, they will be less stressed.

PD makes better converters than the Boondocker, but their best ones are very costly, and all of them would be a complete replacement: That means rewiring of all the 'DC Distribution' fuse board connections. (marking which ones use 20A breakers versus 10A breakers versus 5A breakers as you pull them off the WFCO board, and matching them back up to proper breakers in the PD, and marking "what goes where".) I'll SWAG as a 2-1/2 hour job, instead of 1/2 hour.

[rickst29]

Originally Posted by BrucePerens

I'm not sure about your theory. I would accept that high-frequency noise on the power line could flip an AFCI or dual-function breaker. I would accept that a current imbalance that somehow sends current through the ground wire would trip a GFI. I'm having a lot of problem understanding how the current flow in hot and neutral would be unbalanced in time. Electricity doesn't work that way. There has to be a current return somewhere for current to flow in hot at all, either through neutral or ground, and this all happens at close to the speed of light. There's a velocity factor due to the line impedance that means it's slower than light, but it's negligible.

I'd suspect that if you are seeing a time difference in current flow on hot and neutral, that your traces aren't synchronized. Less expensive 'scopes alternate the traces.

Reactance: The transformer stores some energy, and "barfs it back" in slightly nasty ways during the switching process. But, at the same time, I agree that the WFCO could have leaks between "current carrying neutral" and green-wire "safety ground". The design is Sh#t. (Anyway, when "looking at" WFCO, I was using a borrowed scope - and I don't know if that particular machine was alternating the traces. It was not expensive, you could be right about that.)