AC Panel and "Spare" Circuit Breaker in 32-3

[Norwester]

While installing a new-to-me battery charger, I took more notice to the AC Panel, the 15amp fuses, indicator lights (1 is out) and wiring. A couple questions:
1. What is the "Spare" circuit breaker switch used for? And, when might it be used (pic, below "charger" switch)? (PS. I couldn't find another thread addressing this "spare" breaker.)

2. Why might actual wiring differ from diagram? The actual wiring of the factory installed panel doesn't seem to match the owner's manual's "AC Panel Rear View" diagram in the owner's manual, where it pertains to the line/hot (incoming electricity: solid black in diagram) and load/neutral (returning electricity: solid white in diagram). In diagram, there's a black/hot jumper wire vs. the hot & neutral as in my photo of the back of my panel. (what's going on?)

Thanks for the input.

 

[bigd14]

2. Why might actual wiring differ from diagram?

Previous owners work is top of suspect list, but also maybe a custom request from a buyer when new, the apprentice did it wrong but it still worked, it was a Friday afternoon, etc. It’s worth spending time making a fresh circuit diagram as best you can. Also worth it to replace old wiring, after 40 years things get pretty corroded and beat up. Yours looks pretty good on the photos though.

 

[Loren Beach]

Our panel has a "spare' breaker on the ac side. I would speculate that some buyers might have wanted it for AC, or... something....
But I really do not have the definitive answer.

 

[Filkee]

My “spare” is the inverter.

 

[peaman]

My boat had a Norcold refrigeration system which could run off of 12VDC, or 120V shore power through the "spare" breaker.

 

[Christian Williams]

The indicator lights burn out and are easy, if awkward, to replace. Have to make sure the hole size is right and the style matches current ones. They have gotten ridiculously expensive.

 

[Nick J]

1. What is the "Spare" circuit breaker switch used for? And, when might it be used (pic, below "charger" switch)? (PS. I couldn't find another thread addressing this "spare" breaker.)

2. Why might actual wiring differ from diagram? The actual wiring of the factory installed panel doesn't seem to match the owner's manual's "AC Panel Rear View" diagram in the owner's manual, where it pertains to the line/hot (incoming electricity: solid black in diagram) and load/neutral (returning electricity: solid white in diagram). In diagram, there's a black/hot jumper wire vs. the hot & neutral as in my photo of the back of my panel. (what's going on?)

With a 40 year old boat, the manual should be treated as a general reference or historical artifact. Most of these boats have seen multiple owners and any one of them or the professionals they've hired probably changed something.

The original factory wiring diagram doesn't look to be correct. I'm not sure about the original, but in general the main 30 amp double pole circuit breaker is designed to disconnect both the hot and neutral legs of the circuit. The original drawing you've attached shows bridging only the hot leg across both poles. I don't see the advantage to this. The good news is your main breaker is wired correctly.

The industry has changed somewhat since these boats were first released. the main difference is it's now not accepted to bridge the ground and neutral on board the boat. This should already be done in the pedestal (shore power source) on the dock, and does not need to be done on the boat. Here's a modern AC panel from Blue Sea Systems (note the neutral and ground bus is not connected)



You should be able to fix this by providing a second dedicated ground bus terminal strip to the panel and moving all your grounds to that.

The picture of the back of your panel also shows some discoloration on the blue terminal on the outlet wire. This would indicate a weak connection and should be addressed. Hopefully the wire is still good and it can just be reterminated, but if the wire is black you should look into replacing the AC wiring. This is somewhat common in the receptacle circuit as over the years, users plug heaters, heat guns, and other high amp devices into the circuit. You should also check your shore power receptacle and replace as needed.

A great resources for this is Marinehowto.com:

Shore Power - SmartPlug vs. 1938 - Marine How To

SmartPlug vs. 1938 In today's day and age it is far and few between that I come across products that: #1 Do as they say. #2 Are built to an exceptional standard. #3 Redefine what great is. The SmartPlug is one

marinehowto.com

 

[Norwester]

The picture of the back of your panel also shows some discoloration on the blue terminal on the outlet wire. This would indicate a weak connection and should be addressed. Hopefully the wire is still good and it can just be reterminated, but if the wire is black you should look into replacing the AC wiring.

THANKS!! @Nick J
That's really helpful stuff. I had a feeling that the diagram may be incorrect, but that's generally not my first instinctual reaction to reading manufacturer electrical diagrams.

At my marine electrical class, I'll try to engage instructor the topic of ground/neutral management and how industry has changed practices in such a short period of time, it appears.

The good news is your main breaker is wired correctly.

Yippee!. ..I had nothing to do with it, just happy it's not a another issue to address.

@peaman ...so right! AC freeze or refrigeration. Since Sure Marine is literally at my vessel's dock doorstep, the kind folks who work there and live on our dock will (and have been) key to sourcing & installation support.

The indicator lights burn out and are easy, if awkward, to replace. Have to make sure the hole size is right and the style matches current ones.

Yes...there's a good thread on panel indicator lights...

Panel lights

I would like to change out the lights on my breaker panel. I believe they are the original amber incandescents. Some are burned out and the ones that work are blinding at night so i would like to change to red leds. It's not obvious to me that the bulbs can be removed from the front of the...

ericsonyachts.org