Having an issue with my TBAR / Burnt Neutral Wires

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Having an issue with my TBAR / Burnt Neutral Wires - Had the heater on full blast and noticed a smell coming from the fuse box.
turned off heater and fuse box right away and turned off the power outside.

Ive opened up the unit and found 3 wires have been charred / burnt and almost caught on fire completely.
I looked up what it should look like and mine has 3 / 2 wires connected together leaving the other neutral plugs not screwed in.
imo it doesn't look right could i put them on separate t bar neutral screws instead of having three on one plug?

I put a fan on it right away and turned it back on half hour later after tighting all the screws and no longer using the heater on full blast
Its not getting hot anymore nor is it smelling like it did, please let me know if there is anyone that has any advice.
 

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Having an issue with my TBAR / Burnt Neutral Wires - Had the heater on full blast and noticed a smell coming from the fuse box.
turned off heater and fuse box right away and turned off the power outside.

Ive opened up the unit and found 3 wires have been charred / burnt and almost caught on fire completely.
I looked up what it should look like and mine has 3 / 2 wires connected together leaving the other neutral plugs not screwed in.
imo it doesn't look right could i put them on separate t bar neutral screws instead of having three on one plug?

I put a fan on it right away and turned it back on half hour later after tighting all the screws and no longer using the heater on full blast
Its not getting hot anymore nor is it smelling like it did, please let me know if there is anyone that has any advice.
sadly, classic poor RV workmanship

the conductors are too small for the receptacle, therefore the installer just "poked em in" to fill the hole.
when installing multiple conductors into a single receptacle ( bad practice, but done never the less..) conductors should be spliced ( twisted ) together like this.

1736813859438.png

a preferred way would be to replace the busbar with one that has smaller holes better matching the wire gauge.

without more detailed inspection, It appears the conductors were loose and therefore overheated locally.
 
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Or you could strip the wire back and fold it over itself and twist it. Should never be more that one wire under each screw.
You could also cut the plastic cover off an inline crimp splice and then crimp it on the wire to enlarge the diameter.
1736818039733.png
 
One part of my annual RV inspection is the electrical connections, I nearly always find a loose clamp screw that requires retorqing. . These rolling earthquakes, combined with our wonderfully smooth roads, shake things loose.
As to splicing, every connection creates a bit more resistance in that circuit, but it's not enough to cause problems in a healthy circuit.
 
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Thats a Parallax panel, and many thousands have years of use without issue. I've owned one previously and own one now, and never had a problem. These are probably the best 30 amp power centers ever built. On neutrals you are only allowed to have one wire per terminals, grounds two per terminal. I would replace the bar, and strip back to clean neutral wire, and install and torque down the screws, one wire per hole. You should not have any issues with them.

You should, at least once a year, open the panel and with power removed, check the torque on all neutral, ground and circuit breaker screws, and any other screw terminals in the 120v and 12 volt electrical system. When replacing parts such as this, I would recheck torque in a month or two, and again in 6 months or so, depending on use. An RV is a rolling earthquake and everything needs to be checked once a year.

Parallax 8 position neutral bar with insulator, from Boat and RV Accessories.
PAR-M91500009.jpg

If your circuit breaker stabs are corroded or burned any at all, now would be a good time to replace them also.
4 position breaker stab bar and insulator for Parallax panel.
M081-0512-002.jpg

Charles
 
sadly, classic poor RV workmanship

Copper is a soft metal and may deform resulting in loose/poor connections but what Solarman said is spot on.

I had an issue in my Motor home with the air condiotioners sometime sone worked, sometimes the other both or neither.. Started at the breaker box with trouble shooting.. Noticed wires were lose in the terminals This was a motor home less than six months old) Got out the old #2 Sqare bit and one of them was over 3 turns lose.. This is not "Malleable Copper" lose (About 1/4 to 1/2 turn) this is factory electrician did not even try to tighten the screws loose.

The result.. I now believe many RVers have a few screws loose.. Yup. Those screws.
 
I agree with Charles's recommendation, but I would also take a hard look at the entire situation. What was the wattage of the heater that caused the problem, the maximum current rating of the circuit breaker that supplied it, and the condition of all components of the circuit it was plugged into. A properly sized circuit breaker should have tripped if the circuit was overloaded, but it would not if the problem was a bad connection to the neutral terminal block. If that was a bad connection, that could easily have been the root of the problem but, your picture shows several wires that have been hot and not all were in the suspect connection. If it was a loose connection, very likely all of the connections for wire showing signs of overheating have poor connections. A far better solution if would be to replace that terminal block with a proper one for the wire size used.
 
A properly sized circuit breaker should have tripped if the circuit was overloaded, but it would not if the problem was a bad connection to the neutral terminal block. If that was a bad connection, that could easily have been the root of the problem but, your picture shows several wires that have been hot and not all were in the suspect connection. If it was a loose connection, very likely all of the connections for wire showing signs of overheating have poor connections.
As I said in my post MULTIPLE connections were lose some over 2-3 Full Turns loose. That's "Technician did not tighten them" loose. Not vibration loose.

One of the things my Favorite RV service Tech and I have in common....
Once either of us Retightens a connection. IT STAYS TIGHT.
 
This thread prompted me to go out and take some pics of the Parallax 7300 in my trailer. In the course of looking it over, I realized I had not installed a ferrule on a 10 AWG stranded THHN wire that connects to the neutral bar. I used THHN wire (the stuff you pull thru conduits) in blue smurf flex conduit to connect the outside power inlet to the generator xfer box and also used it to connect from the generator terminal box to the xfer box and the xfer box to the Parallax power center. I had started out not using the ferrules and then went back and installed them. Somehow I missed this neutral bar connection.

The problem with the neutral and ground bars is that you cannot insert the wire thru the bar, because they are backed up by insulators or the box wall. Therefore all wires must be cut square and held fully inserted while you tighten up the screw on the bar. First attachment is the removed neutral wire showing strands that did not get caught by the screw and thus not making good contact with the bar. I used rather long ferrules because I bought them to go thru the 12v ground bar mounted on the floor behind the panel. I think the other pics are obvious what they are.

If you place your wire in the bottom of the hole in the bar and keep it centered while snugging up the screw, it will be fine. It is necessary to exercise due care in performing the work. Carelessness is NOT a good trait in electrical work.

Charles
 

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