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Old 22-11-2008, 17:21   #1
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AC Boxes

In house wiring all connections are made inside metal or plastic boxes - switches, outlets and splices when they occur.

Yet on a boat with mains such as Blue Seas devices - ac selector switches or breaker panel the wiring is left "exposed in the back, ie not enclosed in a box. In a house the breaker panel is in an enclosed box.

What's the deal with AC wiring and "boxes" - are they ABYC required? And what about the mains and selector switch and even shore power inlet? It would seem prudent to isolate and enclose these devices, but I see some contradictory things.
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Old 22-11-2008, 17:31   #2
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the wire side of the AC panel should be accessible with only with tools.
If the DC and AC share a panel board. The AC side wiring should be covered to avoid accidental contact.
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Old 23-11-2008, 03:11   #3
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Quote:
Originally Posted by defjef View Post
... What's the deal with AC wiring and "boxes" - are they ABYC required? ...
YES - All AC connections normally carrying current shall be made within enclosures to protect against shock hazards. This includes panelboards, Switches, Receptacles, and junctions. AC & DC wiring must be physically separated.

See ABYC Section E-11:
http://www.abycinc.org/committees/.%5CE-11.pdf
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Old 23-11-2008, 04:17   #4
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This is kinda interesting since I see a lot of combination AC / DC panels and there doesn't seem to be provisions for isolation or enclosures separating AC from DC. Here is a combination panel

230V AC/DC Rocker Circuit Breaker Panels - Blue Sea Systems

Blue Seas does make boxes to fit over the back of devices in different sizes... but how do you isolate AC and DC wiring on the same panel?

My panels are separate, but I was just curious.
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Old 23-11-2008, 04:59   #5
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Excerpted from the Blue Sea Instructions:
http://bluesea.com/files/resources/i...tions/6639.pdf

* The panel should be installed in a suitable cabinet such that the back
side is not exposed to personnel once installation is complete.
It is recommended that the cabinet closure be such that the back of the panel
cannot be accessed by children or others trying to reach something other
than the electrical system for service.

* An insulating guard should be installed over the AC circuitry to prevent
access when the DC portion of the panel is exposed for service.
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Old 23-11-2008, 19:21   #6
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In planning my rewire that was/is one of my concernes. The original panel of my Endeavour 40 is a/c and d/c together. Plus battery selector, and you get a mess of wires all together.
Originally I was just going to go with a combination panel to save cash, but the more I read, and thought up on it, the more I realized the foolishness of this.
So a full rewire including new loaction for both panels, shore power connector, and wire runs is in order.
I am going to build a box to house ac seperate from d/c.
And of course, a screwdriver will need to be used to access it all.
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Old 23-11-2008, 20:31   #7
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Separating them is also a safety measure for anyone who needs to work on an electrical panel. With a 12 VDC panel you know you are relatively safe. With an AC panel you had better make sure everything is dead first.
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Old 23-11-2008, 23:47   #8
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I was on the ABYC committee that put the requirement in E-11 to separate the AC and DC, and if in the same enclosure, have a cover of some sort over the AC side. The primary concern here is safety. You don't want someone thinking they are working on DC when they are actually working on AC, and you don't want someone working on DC to accidentally make contact with a live AC circuit. So the AC side (if in the same enclosure as the DC) needs to be covered and the cover has to be removed with tools. Something as simple as a plastic barrier will work. It is best to have separate panel boxes but sometimes this is not possible or cost effective.

Also anyone working on AC or Dc should make sure the power is off and dead. When I was a technician in the USCG we used a dead man's stick. It had a cable with an alligator clip that could be clipped to ground, and a metal end to touch to the circuit. The handle was of course non-conductive. You always used this to short capaciters and other circuits to ground before working on the circuit. I recommend shutting the power off, and tagging it with a big red tag that says Do Not Turn Power On. Man Working on Circuit. Do this even if you are the only one on the boat. Stranger things have happened. I have had people ignore the tag and turn the circuit on anyway. But it's better than not tagging the switch.
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Old 24-11-2008, 03:51   #9
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I decided to re do my electrics 2 years ago. I first tackled the DC side which is the vast majority of the wiring. I did everything to ABYC standards.

This Fall I am re doing the AC side. Ripped everything out and installed a selector switch and main panel on the complete opposite side of the boat. The AC wiring is in a relatively inaccessible locker which I have now called my electrical closet. I have a chematic diagram in a plastic sleeve on the inside of the locker door. The electrical closet is also close to the shore power inlet. I moved the inverter to the electrical closet but the #2AWG wires come in from the bottom and are completely isolated from AC wiring which is all triplex marine wire and at the top side of the closet. The battery charger lives in this closet too at the bottom with the inverter. So now all DC wiring and panels. switches etc are on port and all AC on starboard and both with indicator lights and so forth are visible from the entire main cabin.

After tie up the wires I will install a plexi cover on "stand offs" so nothing touch any of the wiring as I have done with the DC wiring on the port side of the engine room. This is would have been the greatest shorting hazard as one works with wrenches on the engine (changing filters and oil for example) and so forth in close proximity to busses, fuse block and so forth.

I've labeled most of the wires using printed labels and clear shrink wrap so I can identify where the wire is going or coming from. Without that it is quite confusing. I continue to add labels when I have time and like a jog saw puzzle it gets easier as you come to the end.

This has been a daunting task,which tool lots of planning and time for execution, but I feel that I have both the DC and the AC under control and up to ABYC standards as they should be. Shiva, as a crusing and once live aboard yacht has loads of electrical devices and gear which has been added over the years... and will be seeing changes in the years to come.

A good job is never done!
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