Bus Electrical (house) problems

yvan · October 09, 2014, 06:26:02 PM

I have a small issue with my electrical system as you can see in the pic it has been "fixed" a few times. This unit both controls 110 and 12v. There is a relay that has a tierwrap holding it on, and I don't have lights in some areas, but all fuses have continuity.

I would like to replace this thing, what do you recommend, one of the breakers shuts off all my 12v.

pennuja · October 09, 2014, 06:32:07 PM

In my airstream I was going to go with one of these because I have glass fuses as well, but I did not do it yet.

http://www.amazon.com/Blue-Sea-Systems-Blade-Block/dp/B000THQ0CQ/ref=sr_1_2?ie=UTF8&qid=1412904921&sr=8-2&keywords=12+volt+fuse+panel

If it was my bus I would also change the breaker panel so that you had 2 separate boxes, but that is just me.

eagle19952 · October 09, 2014, 06:35:17 PM

my first thought is that the coil in the relay must be bad...hence the "holdindevice"...
my next thought would be why would someone use a 110v coiled relay to begin with.

were i you, after deciphering why... eliminate the relay with appropriate manual switching.

Oonrahnjay · October 09, 2014, 07:06:16 PM

mung · October 09, 2014, 07:20:29 PM

First of all, your 12v and 120v should NOT be even close to each other. Use proper panels and fuses for both. For the 120v stuff you are going to want a house type panel with real breakers. For the 12v stuff there are panels with breakers for RVs and boats that will work. Main breaker on both and breakers for each circuit. Please, please, please get them in totally separate boxes. One mistake can cause a world of hurt when mixing the two. Don't use your chassis ground for your 120v system, there is a huge difference between negative on the battery and 120v ground and the two should never meet. Kind of like your wife and your girlfriend, very, very bad things can happen if they meet.

So get proper AC and DC panels and make sure it is very clear which is which and which wires are AC and which are DC.

eagle19952 · October 09, 2014, 07:50:06 PM

although it is not current code...it does look as original vs. backyard engineering...
the scariest thing i see is the bailing wire.
if the AC breaker contacts are fatigued, well that's scary enough to warrant a redo with current electrical updating.
heat arcing by poor contact in an AC panel would not prove beneficial to sound sleeping....

akroyaleagle · October 09, 2014, 09:22:02 PM

I recommend you locate someone that has a clue to redo all that mess.

That is scary.

Things like that and worse are parked next to us and are plugged in at rv parks.

Separating the two is not difficult.

12V house power should come from the batteries with correctly sized wires (not spliced) to a control bus.
There should be a fuse for each load that is connected to this bus. One load, one wire one fuse. Then wire up the next load.

AC power should come from shore power to a switch box. (You have a switch in your photo) From a generator to the switch box (different switch) or from the inverter to the switch box (third switch). The switch box should automatically default to the correct source. (Mine is if I am using inverter only and I plug into shore the shore switch picks up the load and the inverter switch drops it. If I then start the generator, the generator automatically picks up the load and the shore power drops it.)

Whatever the selected source is will then be connected to the breaker panel. Proper sized breakers and wires then would power circuits.

Please get someone to help you clean that up.

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bevans6 · October 10, 2014, 04:37:48 AM

My first reaction was that is an AC distribution box with a built in transfer switch. The upper is obviously the breaker section, the lower looks like a transfer switch and controller, not sure what all the little fuses are for, might be the 12v. I'm with everyone else - take it out, trace it out, replace with modern home or RV distribution panels for AC and DC, and get a new ATS.

Brian

ol713 · October 10, 2014, 08:27:21 AM

Quote from: Oonrahnjay on October 09, 2014, 07:06:16 PM

That's a fine mess. Bet it took awhile to get to look that way.

Merle.

Oonrahnjay · October 10, 2014, 08:30:33 AM

Quote from: ol713 on October 10, 2014, 08:27:21 AM
That's a fine mess. Bet it took awhile to get to look that way. Merle.

I'm just surprised it works at all without killing someone. Just a reminder of how bad wiring/electrics can be ...

yvan · October 10, 2014, 09:06:32 AM

Thanks everyone, and yes I plan on replacing this mess. We do not camp anywhere near shore power, so the 12v stuff will all go and be connected to the battery bank (the PO did no boondocking, so in this box was the 120v power, a transformer to bring it down to 12V dc and a small 12v distribution panel (the fuses)) 120V will only be supplied by the generator, and that will give us power for the AC and central vac. and instead of running a 12v power supply off 120v, when the generator is running it will power a battery charger to supplement and improve the house batteries. An inverter will be put in place as the "normal" 120 power source for the microwave and coffee maker.

MightyThor · October 10, 2014, 09:40:40 AM

Quote from: mung on October 09, 2014, 07:20:29 PM
First of all, your 12v and 120v should NOT be even close to each other. Use proper panels and fuses for both. For the 120v stuff you are going to want a house type panel with real breakers. For the 12v stuff there are panels with breakers for RVs and boats that will work. Main breaker on both and breakers for each circuit. Please, please, please get them in totally separate boxes. One mistake can cause a world of hurt when mixing the two. Don't use your chassis ground for your 120v system, there is a huge difference between negative on the battery and 120v ground and the two should never meet. Kind of like your wife and your girlfriend, very, very bad things can happen if they meet.

So get proper AC and DC panels and make sure it is very clear which is which and which wires are AC and which are DC.

Just to clarify, are you saying that the green/ground wire of a three wire 120 volt system should be prevented from contacting any metal part of the RV? This would require the use of plastic boxes for switches, outlets etc since the ground wire is often hooked to the metal frame of an outlet and thus also to the metal of the box. If the metal boxes are used they are likely to come into some contact with the metal parts of the RV.

bevans6 · October 10, 2014, 10:33:09 AM

Just a small point. It's perfectly OK to have 120VAC and 12VDC in the same "box" as long as they are in separate compartments within the box. that is how almost all RV units are configured. I have such a unit in the bus, handles some of the house AC distribution and the DC distribution in separated compartments, and same in my camper. This unit as pictured appears to have the AC in the top compartment and the DC in the bottom so it was probably legal and to code when it was first installed.

Brian

digesterman · October 10, 2014, 11:07:44 AM

It is ok to, in fact necessary to ground both the DC and AC power to ground, as in the bus steel frame

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mung · October 10, 2014, 11:10:27 AM

Yes Thor, you don't want to use the bus chassis to ground the 120v side, you want it isolated. In true operation a vehicle chassis is never "grounded" it is really negative on a DC circuit (unless you haven't converted from positive "ground" yet). In 120v house wiring ground is literally a ground rod driven into the ground.