30 amp/120v Wiring question...

[Trex]

Last nite I moved Rita to do some repairs on the leveling jacks.... This is when I noticed some burning within my new extention cord on the female plug, (it has a clear body, so you can see the wire conections inside). This is for the 30 amp/120v main plug... used to connect shore power.

Also, there is a GFI box, that I think is an add-on to the wiring system. Looking at Barts comments on another thread, I think I have a loose connection and/or corosion at the plug-in location between the GFI and the extention cord that I purchased when I got Rita.

I've been unplugging at the other end so I didn't notice this new problem before.

My questions are; 1. Should I leave the GFI in place, or remove from system? 2. Rewire system and remove the male/female plugs in front of the GFI, (wire the extension cord direct)? Hire an RV tech to look at my wiring system? 3. Purchase new male/female plugs, (so I can remove the 30 amp extension cord section)... in-front of the GFI?

Or sale Rita....and take the money and run? (just kidding)

Three pics of the GFI box and the male/female plugs.....

[garry]

What gage wire and how long is the extension cord ?

When you unplug from the GFI what does the prongs look like?

From your description it sounds like a poor fit between the GFI and the extension cord causing pitting and corrosion. If so I would replace the male side of the GFI and the female side of the extension cord.

[Trex]

Originally Posted by garry

What gage wire and how long is the extension cord ?

When you unplug from the GFI what does the prongs look like?

From your description it sounds like a poor fit between the GFI and the extension cord causing pitting and corrosion. If so I would replace the male side of the GFI and the female side of the extension cord.

Not sure on the gage of the extension cord....But it's made for RV use... rated at 30 amp, and purchased from Walmart, (15 footer). And there is corrosion on the male plug, in-front of the GFI. And when you plug the male and female together, there is an electrical spark on the one prong that has the most corrosion.

[wmarsha]

if the melting/burning is in the clear end of the extension cord, that means the current being passed by the cord is too much for its contacts. So, either a bigger cord (wire gauge) or less current draw is required. Whenever an extension cord is added to a circuit, it becomes "wounded" to some degree. a fifteen foot cord aint much wire to add to a circuit, but if it is marginal for 30 amps, it will (and apparently has) become a fusible link. Eliminate the ex. cord if possible. I think the GFI box is also a TVSS unit (transient voltage and surge supressor) which means it isn't absolutely required for the circuit to work correctly. So eliminating it will not hurt your experiment. It should draw a small amount of current, but not much. Check your other connections for tell-tale signs of over current-dark, oxidized prongs on the male ends; loose sloppy female ends. if you are unsure of the age of your electrical connectors, then you may wish to replace them-it will be good insurance. run your hand along the length of your shoreline and check for obvious cuts, but also bulges inside the insulation-a sign of a possible kinking of the cable and possible conductor damage. Just check the integrity of one section of your connections at a time until you find what is causing the problem. Now remember, running the air conditioning and a microwave and a heating element (h2o or hair dryer or coffee pot, etc) all at once can easily exceed 30 amps. the EER (easy electrical 'rithmetic) for converting watts to amps is: VA=watts. watts divided by volts will give an approximate amp value; add 'em up and see where you are at. good luck ol' bill

[Jammer]

Rex

The GFI box was added later and is not a necessary or customary wiring practice. It should be removed.

On your trailer the original wiring would have involved a permanently attached shore power cord approximately 25' long. That is what you should put in place now unless you plan to install a Marinco inlet instead.

[Smokin Camel]

If you have a meter, you may want to check the resistance on that prong that sparked. could be a short in the plug itself. It is also possible that a single failure can cause other failures.

Another thought , not the specific problems of shorting, but this possibly could contribute to troubleshooting the problem...is the circuit you are plugged into also on a GFI, is it a 30 amp? If two GFI's are set somewhat sensitive, it could be a minor problem and make diagnosis a bit of a pain.

[Trex]

Originally Posted by Smokin Camel

If you have a meter, you may want to check the resistance on that prong that sparked. could be a short in the plug itself. It is also possible that a single failure can cause other failures.

Another thought , not the specific problems of shorting, but this possibly could contribute to troubleshooting the problem...is the circuit you are plugged into also on a GFI, is it a 30 amp? If two GFI's are set somewhat sensitive, it could be a minor problem and make diagnosis a bit of a pain.

There is a GFI in the Pool/pump room and that is where the 30 amp 125v comes from.... Power going to the Pool room is 220v, and the line going to the shorepower box, (next to the trailer), from the pool room is 10 gage wire, 30 amp/125v.

The extension cord that I am taking about, (which has the burn marks on the female side of the plug), is my shoreline power cord from the trailer to the 30 amp plug-in box next to the trailer. So there is no other extension cords attached to my system here in the backyard.

I'm thinking about removing the male & female plugs and wire direct to the GFI coming out of the back of the trailer....that way, it will be more water proof than the current setup. I keep thinking there must be a reason the PO installed that GFI inline. I may have more of an eletrical problem than just a bad connection between the 30 amp cord from walmart and the male plug, in front of the inline GFI.

I was going to post some photos, but my camera battery just died...so I'll post once the battery is charged.

[Bill M.]

for what it is worth, I always get a spark when I plug my trailer in. The power converter draws quite a bit of power on startup.

[Trex]

Originally Posted by wmarsha

if the melting/burning is in the clear end of the extension cord, that means the current being passed by the cord is too much for its contacts. So, either a bigger cord (wire gauge) or less current draw is required. Whenever an extension cord is added to a circuit, it becomes "wounded" to some degree. a fifteen foot cord aint much wire to add to a circuit, but if it is marginal for 30 amps, it will (and apparently has) become a fusible link. Eliminate the ex. cord if possible. I think the GFI box is also a TVSS unit (transient voltage and surge supressor) which means it isn't absolutely required for the circuit to work correctly. So eliminating it will not hurt your experiment. It should draw a small amount of current, but not much. Check your other connections for tell-tale signs of over current-dark, oxidized prongs on the male ends; loose sloppy female ends. if you are unsure of the age of your electrical connectors, then you may wish to replace them-it will be good insurance. run your hand along the length of your shoreline and check for obvious cuts, but also bulges inside the insulation-a sign of a possible kinking of the cable and possible conductor damage. Just check the integrity of one section of your connections at a time until you find what is causing the problem. Now remember, running the air conditioning and a microwave and a heating element (h2o or hair dryer or coffee pot, etc) all at once can easily exceed 30 amps. the EER (easy electrical 'rithmetic) for converting watts to amps is: VA=watts. watts divided by volts will give an approximate amp value; add 'em up and see where you are at. good luck ol' bill

Thank-you so much, for the feedback/information... The extension cord that I'm tak'in about is the main shorepower-cord, I don't have any other extension cords connected. The GFI add-on is rated at 30amp, 120v and it says that it is for RV's. Looks like they, (the PO), cut the original shoreline and put this GFI in-place and a one foot line, with a male plug. So that is the reason for the use of the 30 amp extension cord. Here's more pics of the issue.

1st Pic shows the burn mark inside the female plug-head.
2nd pic shows 30 amp shorepower box next to trailer.
3rd pic is location of main power...pool room/bathroom.
4th pic is main power box in pool room.

[richinny]

if the main feed for the trailer is already on a gfci the box on the trailer is redundant. get a gfci tester and verify that it works.

the burnt contact ends need to be replaced.

reconnect with the new end on the power cord, put a heavy load on the cord and check the voltage, if the ends heat up and report back.

each connection increases the possibility of corrosion and higher resistance.

have you had any brown outs (low voltage) while using this setup?

[Lance M]

Rex my Man,
I highly recommend you cut that add on stuff off and throw it out with Wednesday's trash. Get yourself a new 25' RV cord and have Porno Bob, Wino Wayne, or whichever friend of yours is an electrician to properly wire it into Rita's AC service box. The original version from 1972 was a good design.

[jdalrymple]

I'll jump in too. The more connections in any circuit, the more resistance. Each plug, male or female, adds a point that is not pure copper wire. It's like having to add 10 psi to your friction loss calculation for each appliance in the line.

I would be completely comfortable with no GFI in the incoming line. My newer trailer has the marinco twist lock on the side of the trailer with the removable cord. I always thought that would be handy. But, I see about a 3-4 volt drop inside the trailer, even when I measure 120 volts at the outlet I'm plugged into. I agree with TOP, the most bestus would be a 20-25' 10 gauge SJ cord wired directly into the main breaker.

[Trex]

Originally Posted by richinny

if the main feed for the trailer is already on a gfci the box on the trailer is redundant. get a gfci tester and verify that it works.

the burnt contact ends need to be replaced.

reconnect with the new end on the power cord, put a heavy load on the cord and check the voltage, if the ends heat up and report back.

each connection increases the possibility of corrosion and higher resistance.

have you had any brown outs (low voltage) while using this setup?

Thank-you for your feedback.... I'll give it a go in the morning...remove the add-on GFI and wire a new shoreline cord to Rita.

[Trex]

Originally Posted by jdalrymple

I'll jump in too. The more connections in any circuit, the more resistance. Each plug, male or female, adds a point that is not pure copper wire. It's like having to add 10 psi to your friction loss calculation for each appliance in the line.

I would be completely comfortable with no GFI in the incoming line. My newer trailer has the marinco twist lock on the side of the trailer with the removable cord. I always thought that would be handy. But, I see about a 3-4 volt drop inside the trailer, even when I measure 120 volts at the outlet I'm plugged into. I agree with TOP, the most bestus would be a 20-25' 10 gauge SJ cord wired directly into the main breaker.

10-4...thanks for the feed back Mr. jda & TOP. I hear what you're say'in.