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12V Neutral wiring

Posted: March 15th, 2024, 2:21 pm
by pwillis@mail.com
I recently purchased a new electric toilet and I had to upgrade the circuit breaker and wiring for the installation. I have a 1999 406 aft cabin. Is there a "neutral bar" or gang connection for neutral wiring in the bow area of the boat? How about the stern? Thank you!!

Re: 12V Neutral wiring

Posted: March 16th, 2024, 6:08 pm
by pepmyster
I know in my 360 SS there are buss bars in the stern, also, should be behind your main breaker panels.

Re: 12V Neutral wiring

Posted: March 16th, 2024, 10:33 pm
by bud37
pwillis@mail.com wrote:Source of the post I recently purchased a new electric toilet and I had to upgrade the circuit breaker and wiring for the installation. I have a 1999 406 aft cabin. Is there a "neutral bar" or gang connection for neutral wiring in the bow area of the boat? How about the stern? Thank you!!


Do you mean 12 volt dc, if so there is no neutral per se only a negative , ground side. I think this is what you are talking about , but still to be sure.

Re: 12V Neutral wiring

Posted: March 17th, 2024, 11:47 am
by pwillis@mail.com
Yes, the negative side. I just thought there would be a bus bar or something in one or two areas of the boat. I can't find it.

Re: 12V Neutral wiring

Posted: March 17th, 2024, 12:12 pm
by km1125
I'd be surprised if there wasn't! Hopefully some other 405/406 owners who've done wiring will chime in.

Re: 12V Neutral wiring

Posted: March 19th, 2024, 4:10 am
by Phrancus
You may want to get someone with some experience in electrics if you can't find a negative in a boat....

That was not very kind :blush: to say but:

1) find any other aplliance and follow the leads. But you mention that you had to change the fuses and the wiring, did you only put in a new positive lead then? Why not both at the same time?

2) check and confirm that the points you find are capable of handling the currents that your toilet pulls when in operation.

You don't want to connect to anywhere and hope that furtheron from there to the battery a thinner line was used because the expected load was for a lightbulb, not an electric toilet that can get stuck and the positive doesn't blow the fuse in time before the thin lead starts to melt and burn.

With such potential currents, I'd use new wiring all the way to the fuse box and there connect to the bar and a properly sized fuse.

(also because trouble over time often starts at negative bus bars hidden somewhere and you do not want to have trouble with a toilet. That trouble usually surfaces when the toilet was just used......... :-( ) guess how I know.....

Re: 12V Neutral wiring

Posted: March 19th, 2024, 8:03 am
by pwillis@mail.com
Thank you!! I did pull a new 10 gauge wire from the toilet controls to the new 20 amp circuit breaker that I put in the panel. On the negative side I used the 10 gauge wire that was used for the old vacuflush system because I couldn't find the negative bus bar. I disconnected the positive side of the old vacuflush system and capped off the old wires and marked them abandoned. Just can't seem to find that negative bus bar!! :banghead: Thanks to everyone for your suggestions and advice!!!

Re: 12V Neutral wiring

Posted: March 19th, 2024, 11:54 am
by bud37
pwillis@mail.com wrote:Source of the post On the negative side I used the 10 gauge wire that was used for the old vacuflush system because I couldn't find the negative bus bar


I think that is the right way. ... :down:

Also I believe that you may have answered your own question about bus bars, as the original was originally wired all the way back to the panel.

Re: 12V Neutral wiring

Posted: March 19th, 2024, 10:21 pm
by Viper
I've found that only recently have most manufacturers installed busbars in areas other than behind the electrical panel and helms. They've been installing main busbars (battery cable bus) in the engine compartments that are easily accessible for hooking up accessories. They also offer the ability to hook up main cables to the bars and minimize multiple cables on battery terminals which is the best way to go.

Re: 12V Neutral wiring

Posted: March 20th, 2024, 9:57 am
by Wsullivan71
According to the 2002 Carver Owner's Guide:

"Your boat's 12 volt DC electrical system, AC electrical system, and the batteries' negative leads are all connected to the bonding system through buss bars. The buss bars are located in the engine and aft bilge compartments and are connected to the transom-mounted zinc plate."