1969 Chris Craft Roamer 46 Refit: Main Breaker Install

I want to have the shore power system commissioned before the boat splashes. It doesn’t need to be completely done, with all circuits finished, but I don’t want to have to keep using extension cords to get power inside the boat.

I’m using a Furrion 125/250v 50 amp shore power inlet that I installed under the bow seat. That was a vast improvement over Chris Craft’s original approach, and I also want to make access to the main breaker easier. Mine was originally in a box in the anchor rode locker in front of the v-berth front bulkhead. I’m thinking a cabinet in the galley would be better.

Chris Craft’s original shore power inlet installation was bad

In December 2007, I took the picture above. Between the anchor and the dock box is a bollard for tying off the bow lines. Between that and the dock box is the original shore power inlet. It was oriented straight up, so water falling on the deck stood a good chance of finding its way into that 250VAC 50A power inlet.

I’ll install the main breaker in the corner of the upper galley cabinet

It’ll be out of sight but easily accessible when I’m done.

The enclosure will fit nice and tight in that corner

The American Yacht and Boat Council, which sets standards that most if not all insurance companies in the US follow, requires the main breaker to be within five feet (IIRC) of the shore power inlet. They also have recently updated standards to recommend GFI main breakers, in an effort to reduce drownings caused by boats leaking electricity in fresh water. Since electricity will always take the easiest path, a human body in fresh water offers a salty path for stray current to blast through. Even a strong swimmer can be paralyzed by stray current, so I think it makes sense for most boats to have GFI main breakers, which will trip if the current on the return trip doesn’t very closely match the current that went into the boat.

My main breaker is within four feet of the inlet, so even though my boat doesn’t have to meet the standards for new boats, it does meet that one. But I’m not going with a GFI main breaker.

In October, I did a test of my OEM isolation transformer. When I put 240vac to it, it hummed really loudly. It’s in the original location, up in the V-berth, but I could clearly hear it humming away in the aft stateroom. That’s loud. It would be impossible to sleep in the V-berth with the racket that transformer was making.

I checked the voltage at the breaker panel, and it showed 240v, so it was putting out the right amount of power. On a whim I checked L1 and the neutral leg, which should have been 120v…it was 175! When I checked L2 and neutral, it was 65!!!

175 + 65 = 240, but that’s a serious imbalance in the output. When I reinstalled the isolation transformer in 2016, I removed the original cables one at a time and installed new #6 cables exactly as it was originally configured. Presumably, between 1969 and 2022, something shorted inside the transformer, not enough to make the smoke come out but enough to seriously throw off the output balance AND make it hum badly.

So, after doing a bunch of investigating, I made the decision to upgrade the isolation transformer to Marine Pucks from Bridgeport Magnetics. For reasons I’ll get into in my next post, Marine Pucks make GFI main breakers unnecessary. In fact, the manufacturer recommends not even bringing the neutral or ground cables onboard boats that have Marine Pucks.

An ABYC-compliant marine-grade electric leakage current interrupting 50 amp main breaker runs ~$400. But I’m a big fan of FactoryMation miniature circuit breakers. A 50 amp D-curve (recommended by Bridgeport Magnetics) 2-pole breaker with enclosure was a whopping $46 with shipping.

The perfect spot

Time to break out the Harbor Freight oscillating saw

I haven’t been in here in a while

Furrion shore power inlet installed with some weather protection

It’s not perfectly protected from the elements, but being under the bow deck seat and angled down ensures water will have a tougher time finding its way to the tinned copper connections inside.

I removed the Furrion inlet temporarily and disconnected the white neutral and green ground cables, then pulled them from the loom in the galley. There’s no chance of a pesky shore power earth ground sneaking its way aboard now.

Down below, I removed the p-clamps and pulled cables out of the loom

That green ground cable is coming out, per Bridgeport Magnetics’ instructions.

Good riddance to unnecessary grounds

That looks about right

I’ve had the pretty mahogany panel that goes to the right of the main breaker done and ready to install for several years. But I need to install some backing cleats around the perimeter so it has something to attach to. As we found during the demolition phase years ago, the original panels on both sides, and the entire forward bulkhead were rotted out from water coming through the original bow seat windows.

I wetted out mahogany cleats with epoxy

Wood flour-thickened epoxy will glue the cleats to the original panels above and below the new panel

Cleats are glued and screwed in place

Next day, the epoxy’s cured

Pulling the #6 cable up from the bilge below the galley after cutting the connections at the transformer

L1 (black) and L2 (red) are ready to be connected to the breaker

Holes drilled in the panel for the cables

A dab of caulk on the cables makes a great cable clamp.

Cables attached to the new 50a breaker

I applied epoxy to the panel and backing cleats, then mooshed it all together with a push stick and clamp

Nice!

That looks pretty good!

I’ll put bungs in the screw holes of the original mahogany panels later, then apply ICA top coat. That’s not a priority right now. But with the 50 amp main breaker installed, the last step to commissioning the 250/125VAC breaker panel is installing transformers that work.

Next up in our 1969 Chris Craft Roamer 46 Refit: Installing 12kva Bridgeport Magnetics Marine Pucks!