Visit our Popular Forums

romakdaddy · 09-24-2013, 06:59 PM

so if anyone remembers I redid my breaker box earlier due to someone making a mess out of it http://www.airforums.com/forums/f37/...ly-108627.html ...anyway its been doing great sitting in the yard so I thought id tackle adding a switch and second 20 amp cord to the front air unit so I can run it without the gen having to be on(2 way switch one position for shore power and the other for gen power)
long story short I had power on the MH running whilst fidgeting with the connections in the gen housing going into the coach. I identified the main feed and the ac feed going in and tested them for live ckt and it was all dead so I proceeded to disconnect the wires. I unhooked the hot(black) wires no big deal but when I unhooked the neutral(white) wires something odd happened...the main neutral went fine unhooking but the ac neutral gave me a slight shock and the rear ac quit and I heard the switchover relay in the inverter click every now and then like it did before I ran the proper sized wires from the house breaker to shore cord. it seems there's something going on with the front air neutral and the rest of the coaches system. I made sure to separate all the grounds and neutrals in the breaker box but I did notice while doing the rewire that the ground and neutral on the inverter wires seemed to be connected...is this normal? what should I look for?...ok long short story over...lol

DanielB · 09-24-2013, 07:04 PM

.......

cwf · 09-24-2013, 07:18 PM

I think you need to look for an electrician...

romakdaddy · 09-24-2013, 07:31 PM

perhaps you're right but I'm a die hard(and possibly some day died hard) do it yourselfer...lol

r carl · 09-24-2013, 07:57 PM

Quote:

Originally Posted by romakdaddy

perhaps you're right but I'm a die hard(and possibly some day died hard) do it yourselfer...lol

Possibly from an electrically hot airstream.

garry · 09-24-2013, 08:49 PM

It's been a long tome since I rewired my SOB but (if I remember right) the transfer switch does not switch the neutral and in effect you have an open neutral and are running the ac on hot and ground.

I rewired the rear not the front so it may not be the same but I did have to switch both neutral and hot because of the way the generator tied into the main box.

I just looked at your rewire post I hope you have "not" tied the neutral wire to the ground wire in the breaker box as this would be a big time no no..

RM66caravel · 09-24-2013, 10:55 PM

Okay I have read this 3 times trying to see what you have done and if I read it right you ran a second line to the ac from a switch? Think logic or gate 2 lines in 1 line out switch only determines which input to use. so line from generator or where ever it came from in the begining is input 1 switch position 1 and ac line from house is input 2 or switch position 2. never share inputs hot or neutral and you should be fine as long as you wired the ac in the AS correctly which I am assuming you did. S quick check at the ac to make certain that the hot is the ac hot (air conditioner) not talking down cause I have been in wireing for 20 years and still on a rare occassion arch a screw driver or 2.
Cliff and I hope this helps

romakdaddy · 09-25-2013, 06:29 AM

Quote:

Originally Posted by RM66caravel

Okay I have read this 3 times trying to see what you have done and if I read it right you ran a second line to the ac from a switch? Think logic or gate 2 lines in 1 line out switch only determines which input to use. so line from generator or where ever it came from in the begining is input 1 switch position 1 and ac line from house is input 2 or switch position 2. never share inputs hot or neutral and you should be fine as long as you wired the ac in the AS correctly which I am assuming you did. S quick check at the ac to make certain that the hot is the ac hot (air conditioner) not talking down cause I have been in wireing for 20 years and still on a rare occassion arch a screw driver or 2.
Cliff and I hope this helps

The switch isn't wired yet till I figure out why the whole system will only run satisfactory with neutral hooked up to the front ac input line in the gen housing. but the idea of the switch is a SPDT with the input leg going to the front ac hot wire and the other legs one going to a shore connector and the other going to the gen output.
On the neutral issue I've been thinking about the switchover relay in the panel box maybe I have dirty contacts on the neutral side...ill look into that(not on a live circuit folks) when I get home today. This may have something to do with the G/N bonding I noticed. If I'm not mistaken shouldn't the ground and neutral be totally isolated?

RM66caravel · 09-25-2013, 03:00 PM

Yes ground and neutral are always separate but sounds like you are doing great.
Cliff

romakdaddy · 09-25-2013, 07:05 PM

too tired today to tackle the lectric problem plus it was threatening to rain so ill give it a whirl tomorrow.on a related note I was able to power the front ac using an external cord so I know it works now.

romakdaddy · 09-26-2013, 08:51 AM

another question IIRC the neutral coming directly from the generator has continuity to the chassis of the MH. should the neutral and ground in the generator not be bonded?

romakdaddy · 09-26-2013, 04:45 PM

WOOT!! I found the problem with the neutral acting the fool.... seems I was right in checking the gen switchover relay...the neutral side has lost continuity from feed leg to the other terminals...looked closer and the little braided wire was burnt in two....there's my loss of neutral so its off to find a new relay. but I still have a bonding issue I've traced to the output on the inverter(trace u2512) and the generator(onan emerald 3).

romakdaddy · 09-28-2013, 12:38 PM

starting to talk to myself now it seems but I'm just sharing my findings. still waiting on the relay but in the mean time I've researched the bonding issue and it seems its supposed to be that way so all is normal with the inverter and generator having the neutral/ground bonded.

cwf · 09-28-2013, 04:51 PM

Excellent!!!! Congrats!

romakdaddy · 10-10-2013, 08:34 AM

Finally got the relay replaced and did a couple of other mods. I got the switch for the front AC done so that I can run it on shore power and it works perfectly except the unit isn't cooling. I also ran a separate circuit for the dometic fridge since it was blowing the GFI breaker after a few minutes. The element is getting hot(not sure how hot) but the fridge isn't cooling(ill make a new thread for those issues later). here's the relays (old vs new)

Jammer · 10-10-2013, 01:19 PM

Those flex braid things don't just burn up like that for no reason or out of regular wear and tear. That thing lived through a dead short, a lightning hit, or a 10x overload.

Bonding, grounding, and neutral switching with transfer switches is a difficult topic. Approaches have changed over the years and manufacturers recommendations aren't consistent; also, the approach in RVs is generally not the same as the approach in buildings. Caveat lector.

If you are using an SPDT switch to choose power sources that means you aren't switching the neutral. Three problems with that, one, the neutral blade on your separate 20a plug for the air conditioner may carry a few volts to ground, enough for a bad shock, as a result of voltage drop in the neutral on the 30a shore power cord and associated wiring. Second problem if you connect it to a miswired outlet with reverse polarity it will blow up in your hand. Third problem is that you're running the 30a and 20a neutrals in parallel essentially and so if there is an open or a high resistance on the 30a shore power cord you'll have up to 50a going through the neutral on the 20a cord. No breaker or fuse because its the neutral so your first indication that something is wrong may be the sirens from the local FD.

This sort of thing is why the NEC doesn't allow multiple service entrances (except in rare cases in exceptionally large facilities).

My rig is wired for 50a which is the right way to do this.

romakdaddy · 10-10-2013, 03:03 PM

not sure what blew the braid but it was the neutral side of the ckt not the hot the braid looked kinda wimpy especially compared to the new relay but the old relay was marked to be 30a and the new ones 40a but that's a big difference for 10 more amps...either way all is working normal now.
on the ac mod, the input power is not going th be tied into the 30a service cord but it will have a separate drop cord hooking into the 20a park/home outlet. I've read on several forums that this is a more cost effective way to run the front ac without the gen running or having to run a new service entrance cord and panel box. The neutral will be tied into the neutral the gen feeds the circuit and the ground will be tied to the chassis like it should be, yes im only switching the hot side but in my limited knowledge of electrical it seems to make sense. I did make a diagram to demonstrate this mod if you can understand my cryptic drawing style...lol

romakdaddy · 10-10-2013, 08:27 PM

but hopefully I get points for making it look good...lol

oliver00 · 10-11-2013, 04:41 AM

Why not just install a 50 amp transfer switch. It will do all of this for you plus have extra capacity.

romakdaddy · 10-11-2013, 05:39 AM

if I understand it correctly, in order to take advantage of 50a service you need a 4 wire shore cable (2 120 hots 1 neutral and 1 ground) the 30a cord only has 3 wires (1 hot 1 neutral and 1 ground) the front ac circuit is independent anyway since it is originally wired only to the gen (gen has 2 120 outputs 1 30a to the coach and 1 20a to the front ac) I just took advantage of the separation and added a second input to the front ac circuit. I know ill have to make sure that both plugs are wired correctly but its a good habit to check regardless from what ive read.