Sounds to me it's exactly like my GFI outlet. It simply can't handle having the block heater plugged into it. I bet it's much less than a 15 amp outlet.

Also that test light won't draw enough to trip the GFI. So it's going to test normal unless the circuit itself is grounded.

 

Plug it into an outlet that does not have a GFI. If it doesn't trip the breaker, it's good. And I bet it's good!

 

One thing to keep in mind here guys is this. Very few, almost no houses have single dedicated circuits anymore. Meaning that the GFCI is rated for 15 amps, however what else is on that circuit? It is probably wired with at least 3 outlets with it, and maybe some lights as well. A good upgrade for any home workshop is at least 1 dedicated 110 outlet with a 20 amp breaker. It will run any tools without tripping breakers. Another is to keep the garage seperate from any household wiring. Heck, the high frequency from my tig welder would set off my GFCI's in my old house, and it was fairly new wiring and met all codes.

 

As far as I know, the GFI outlet that I was having problems with has nothing else on it. The only other thing I have plugged into it is a trickle charger for my generator battery.

My house is kind of odd though. The guy that I bought it from is that one that had it built. My understanding is that he kept running out of money and firing contractors, so who knows who put one in. He also built the house so that there was a separate apartment in it for a relative; the house therefore has two furnaces and two fuse boxes.

I seem to recall when I had siding put on that the siding guys tripped it too, so it may just be a "weak" outlet.

 

The block heater on the 6.0L PSd motor is +1,200 watts and maybe close to 1,300 watts (from memory). Have no idea what is on the gas version... but I would guess close to the same???

 

Block heater on mine 06 f150 5.4 is 750 watts or so. Should be the same on a f250 w/5.4 also.

 

Best reply I have seen on this thread. GFI's have a line and load side on the back and if other outlets are on the load side and drawing current, then the sudden connection of the heater cord trips the GFI. Also as other have stated, not all GFI's are equal and some can be below rated spec and trip quicker than they should. GFI outlets are expensive to make and many of the big name brands have offshored the manufacter to China on these items. I recently had to rewire a 50 year old house and installed about 10 of these GFI outlets the last two weeks.

Hootbro

 

There's a reason why all outside outlets, basement outlets, kitchen outlets, and bathroom outlets are GFI protected. Not just because the NEC didn't have anything better to do, either. Anytime you're working around a damp, or possibly wet location, you want to have GFI protection. All it takes is one person standing in water and accidentally touch the hot leg on an unprotected outlet before they get nailed pretty good.

Being an electrician myself, it's a pain in the butt to install GFI's in certain areas and get them to work right, but it's not a bad idea to have. What I think is bogus is the Arc Fault protection breakers, which will be mandated to be put throughout the house in the 2008 edition of the NEC, and not just in bedrooms. Those, folks, are a major pain.

 

Well....the block heater did work fine plugged into the non-GFI outlet. Could hear the gurgling this morning when I started it up, and warm air came out immediately.

Chad - I agree re: the reasons for the GFI. I will have an electrician replace the GFI that keeps tripping, as I am not very comfortable using a non-GFI outlet when the end of the cord is outside in the rain, ice, and snow.

 

I agree man. You know the NFPA and the manufcturers got together on that one.

 

Don't get me wrong. You're not going to burn down your house just because your block heater is plugged into a non protected outlet haha. I've seen some pretty crazy stuff, trust me, and this isn't even CLOSE to being a bad problem. And chances are, you're not going to get zapped. But that little chance is there, and I'd hate to see anyone get hurt.

If you lived close, I'd be over this weekend to change out that GFI for ya. But I have no idea where you live haha.

 

I think the GFI discussion is a good one, but don't assume that just because it works in a non-GFI outlet that the outlet is the problem. As mentioned before, I had the exact same problem you experienced and the problem ended being mag chloride and road salts built up on my block heater chord connections; leading to current leakage. Once I cleaned those up, and sealed them to prevent future exposoure, my block heater is working fine in my GFI outlet - along with the freezer in my garage. The circuit breaker will trip if my block heater is on (I'm on a timer) and my freezer is actively running and my girls fire up their hairdryers - all at the same time. Not sure where you live, but do they use mag choride in your area to counter snow/ice?

You may end up replacing your GFI outlet, just to experience the same thing if you don't zero in on the actual problem. They are designed to trip for a reason and you should rule out those possibilities. Not to sound silly, but if your bathroom GFI tripped while you grabbed the the radio while getting out of shower what you do?

Mark

 

Is the answer.... "Quit taking showers or get a new radio?"

 

Good one Beach! Anything but "Change the bad GFI" or "plug the radio into another outlet that is not protected"

Beach, as I know you use a Marinco plug also, remove the rubber boot behind it sometime and have a look. I was surprise how nasty mine was inside and the source of my problem I believe. In researching my problem, I did hear of some situations where the chord connection on the engine had a build up and was the source of the problem, so its best to assess/cleanup all connection points.

Mark

 

I've not used my engine heater on my '03 F250 6.0L PSD, but my brother-in-law generally has to use his on his '95 F350 7.3L PSD whenever the temp drops into the 40's or below, or that 7.3 gets really hard to start. (new glow plug / relay, etc). He's got about 240K miles on it.

I've noticed that his extension cord running the heater block gets REALLY warm.

My guess like the others is that the GFI on that circuit wouldn't handle it.

rgds,
TX