Please check your 120v wiring

INSPECTORBOB · 09-27-2010, 05:17 PM

I had a strange electrical problem with my (new to me) rig, a 2000 Itasca 35u. I keep the rig in storage, but bring it home occasionally to work on it. When it is home, I plug it into an outlet in my garage that is on a GFI. Often times, the GFI in the garage would intermittantly trip. I just chalked it up to some dampness in the electrical system, because everything in the rig always worked fine when I plugged it into a non-GFI protected outlet.

This week-end, I could not get the garage GFI to stop tripping. I figured that it has been real hot in California, and with no dampness, something must really be wrong. The generator powered everything ok, and everything worked when I plugged the rig into a non-GFI outlet. I started opening up outlet boxes any where I thought water could have migrated, like the outside receptacles and junction boxes, but everything looked fine.

I noticed that one of the legs on the 30 amp plug looked a little discolored, but nothing real obvious. However, this was my first clue. Following the cord, I opened the power switch and checked all the connections on the buss bar. Bingo! The white (neutral) was very loose. In addition, the wire exhibited severe arcing, and the insulation looked like it had been burned. After checking all the terminals, I found most of them needed to be tightened. I decided to also open the breaker panel and check the connections on the buss bars and breakers. These were also loose!

I'm not an electrician, but am retired home inspector. This was a fire waiting to happen. Please be sure to check your 120v wiring connections, and tighten any that are loose. Poor contact causes very high resistance, which makes the electrical system over-heat and possibly cause fires. The breakers will not trip to alert you to this condition! Obviously be sure the power is disconnected before working on any panels, and get the aid of a licensed electrician if you are not sure of what you are doing.

Bob

frankdamp · 09-27-2010, 10:16 PM

That's a real wake-up call, Bob. I accidentally ripped the umbilical out of the automatic change-over relay box by running over it. There wasn't enough slack in the cable for the duallies to pass over it!

Whan I took the old relay box off, three of the terminals weren't tight, so I guess my ineptitude allowed me to dodge a bullet. I now have index cards that can be Velcro-ed on the dashboard saying "Electrical cord attached", "Water hose attached" and "Sewer hose attached". I have them on my post-docking checklist. Don't need any more "sudden twangs".

Petro · 09-28-2010, 08:36 AM

Bob;

Thanks for taking the time to make your post. It should be a wake up call. I am sure there are more like problems out on the trail. There is a saying my buddy always tells me. Put your cottage on the bed of a truck and drive it 65 MPH around the country and see what gets loose.

Don

Luv2go · 09-28-2010, 09:00 AM

Several years ago we were camping in front of my in-laws house with our old coach. We started smelling something like plastic burning. After the initial panic where I got everyone out of the coach and the power disconnected I opened the electrical box and found several neutral wires with insulation charred and melting. Almost all the neutrals were loose.

With the frequency of posts I have seen like this I suspect this is more common than I thought. Needless to say, I check the box wiring periodically nowadays.

They are fairly easy to check, as inspectorbob suggested, just disconnect your shore cord, make sure any inverter/generator is off, open your breaker panel (usually 4 screws, then pull the cover off) and check all the screws you see wires going to. In most cases, there will be bare copper wires going to a ground bar, white wires going to a neutral bar and black or red wires going to your breakers.

Stewart

wa8yxm · 09-28-2010, 10:52 AM

Quote:

Originally Posted by INSPECTORBOB

I

I noticed that one of the legs on the 30 amp plug looked a little discolored, but nothing real obvious. However, this was my first clue. Following the cord, I opened the power switch and checked all the connections on the buss bar. Bingo! The white (neutral) was very loose.

Bob, if you follow my posts then you will know I'm fond of saying that many RVers have a few screws loose.

I see you found the very screws I am speaking of when I type that.

By the way.. When I first got my rig everything worked, but then suddenly I had issues with the air conditioners.. sometimes one would work, sometimes the other, occasionally both (I DO NOT HAVE AN EMS)

sure enough, when I opened up the breaker box and "Attacked" with the old #2 Square bit.. some of those screws took well over a full turn, IN fact I think the winner was 2.5 turns or about that. Before I was happy.

OH and the problem with the A/C... Have not had one since.

INSPECTORBOB · 09-28-2010, 05:51 PM

I'm glad you were able to find it before it caused some real serious trouble. In my home inspection days, I was always finding fried wires in panels that were caused by loose connections. It wouldn't be a bad idea to check house wiring occasionally as well.

Bob

INSPECTORBOB · 06-16-2017, 09:41 AM

My original post had to do with checking your 120v wiring. Thought I would share what I found with my 12v wiring. The dash air in my 2000 Suncruiser (35' F53) just didn't seem to be very strong. My immediate assumption was it must be a blend door, or a vacuum problem, or heater valve that was stuck open, or ??. I poked under the dash to first see if any of the vacuum lines were damaged or disconnected. Everything was fine.

Then I checked the controls, and everything worked there, too. Fan worked, but not very strong, so I thought maybe one of the air ducts was leaking. Nope. After about 2 hours poking under the dash, I happend to reach back to manually activate one of the vacuum motors, and found one of the wires I had accidentally touched was really HOT! I traced the wire back to the nylon connector, and found that the connector was extremely hot as well. There were 4 wires coming out of the connector, which I disconnected. The dash fan immediately shut off. Inspecting the connector further, I could see that some of the insulation around the wire inside the connector had discolored significantly from the heat.

I let the connector cool, and plugged it back in and removed it several times to make sure I had a good connection. Much to my surprise the dash fan output felt like it was now blowing twice as hard! Furthermore, the connector remained cool, even after running the fan for an extended time.

There are tons of connections in a rig, and certainly can't reach or find all of them, but I intend to make it a project to find as many as possible, and disconnect/reconnect or tighten as many as I can. It wouldn't hurt to apply some dielectric lube on them to keep them from corroding. Bad connections create high resistance, which leads to heat. Thank goodness I found this one before heat became a fire.

This didn't fix my lack of cooling problem, which I will continue to research, but it sure did wonders for my fan output!!

Billfish636 · 06-16-2017, 01:07 PM

I am new to all of this. I just signed up for DTNA (a Daimler website) after reading about it on here in year's past posts. I wonder, can anyone open a page from the link? Let's find out. The subject is Electrical Terminal Protection. Some electrical connections are located outside the cab...

https://cmspublish-dtna.prd.freightl...R=QzcwSk9HTjE=

Well, it opens for me in Preview, maybe because I'm signed in. Let me sign out. Still works in Preview.

INSPECTORBOB · 06-17-2017, 09:56 AM

Bill,
It's asking me for a password.

Bob

cbeierl · 06-17-2017, 11:03 AM

Quote:

Originally Posted by INSPECTORBOB

Bill,
It's asking me for a password.

Bob

Yes, you'll need to login to access that on DTNAConnect (formerly AccessFreightliner).

Billfish636 · 06-18-2017, 11:28 AM

Bob,

Aw. Shucks. I clicked on that link again today and it still opened. DTNA was not open. Apparently, once signed in always signed or some log in magic.

Go here: https://dtnacontent-dtna.prd.freight...rica.html.html

oh, heck. skip that step and the next step and go straight to registration:

https://dtnacontent-dtna.prd.freight...questForm.html

The previous posts I recall reading suggested inputting a business name was required. (See the red asterisk) I used my name. Re-access at least every 89 days or password blows up or something.

I was really surprised because I applied on a weekend and was accepted within a few hours.

doorguy · 06-18-2017, 06:39 PM

The transfer switch box on ours has hex driven tighteners on each terminal and I check them regularly. There is also a torque spec on those tighteners, although i don't have the figure with me right now.

Billfish636 · 06-28-2017, 12:48 PM

Some of the data is not too complicated to recall parts of it. For Dielectric sprays use red enamel 3M 1602 IVI. For brush on use Glyptal 1201E.

For Dielectric grease lithium based use Fiske Brothers Lupriplate DS-ES. For synthetic use Nye Nyogel 760G.

Red enamel goes on starter, alternator, ground connections, and battery connections outside the battery box. This part is easy, I can look at mine and see what is still red! For example, almost the entire area around my air filter canister and engine battery compartment is red.

The lithium dielectric grease is used on non-LED tail lamp sockets, battery terminals, Inverter power connections and 7-way cable boots.

The synthetic dielectric grease is used in low voltage serial connection data circuits

The general instructions include using masking tape to protect printed labels when using spray and disconnecting then cleaning before applying dielectric.
__________________
2016 Winnebago Solei
Blue Ox Brake Buddy Chevy Cobalt

bobmac · 07-01-2017, 09:28 PM

I make it a habit of checking and tightening annually all the AC power connections in the transfer switch, the main breaker box and the breaker box for the inverter circuits. Each of these points can be a source of potential failure particularily the transfer switch. I would suggest this is excellent way to avoid problems and all work should be done with the AC supply disconnected, the inverter off and the battery supplying the inverter off.
Also - never dismiss a tripping GFCI. They often fail and if it trips, first replace it with a new GFCI and if the problem isnt resolved, you need to start searching for the issue causing the problem. Good luck,