120v 50a

[oscarvan]

We have a 1977, 58' yachtfish with same electrical panels a you posted. The 220v feed from port or starboard receptacles will feed through switch S5 both 110v legs and the 220v loads ( stove & washer/dryer). Looking at the electrical diagram,each 110v receptaclecan feed only 110v loads. One receptacle feeds one leg, the other would feed the other leg. Each leg is selected through S1or S2. But i cannot see that those two legs could be combined to create 220v.

That's what I was thinking.

[oscarvan]

Not sure if you'll be able to read this. I'm not 100% sure as the 5 position switches are quite intricate in pictorial format.... But I think it shows there is no pathway.

[Photolomy]

Not sure if you'll be able to read this. I'm not 100% sure as the 5 position switches are quite intricate in pictorial format.... But I think it shows there is no pathway.

You don't clearly see how S1 and S2 feeds S5 which then feeds the bus in that diagram?

[oscarvan]

You don't clearly see how S1 and S2 feeds S5 which then feeds the bus in that diagram?

Not really. The X-s indicate which connections are made with the switch in the various positions and then the lines on the left indicate which connection connects to which, and there are quite a few permutations.

I see the pathway from S5, with P or SB 220V, to S1 S2 and with those selected in 220V on to the 110 distribution panel. But I don't see the pathway to the 220V breakers from 110V selected on S1 to S5 and then on to the 220V breakers.

[Photolomy]

My schematic is on the boat, but there was enough of yours to figure out what is connected when.

S5 drives S1/S2, not the other way around.


The AC breaker panel at the bottom has three inputs. L1, L2 and N. The 110v breakers on the left side are connected to L1 and N (giving 110v). The 110v breakers on the right side are connected to L2 and N (giving 110v). The 220v breakers at the bottom are connected to L1 and L2 (giving 220v). The 110v breakers and 220v breakers are all part of the same bus, they are not separate.

The distribution switches S1, S2 and S5 determine how L1 and L2 are powered. N is connected throughout the boat.

S1 determines if L1 is coming from the 220v source (S5), the port side 110v cord or the stbd side 110v cord.

S2 determines if L2 is coming from the 220v source (S5), the port side 110v cord or the stbd side 110v cord.

IF you are using a 220v source, then S5 determines if that source is the generator, the port side 220v cord or the stbd side 220v cord.

If you are using a 220v source, the flow is S5 to S1/S2 to AC breakers.

If you are using a 110v source, the flow is S1/S2 to AC breakers. (S5 doesn't matter).

The neutrals from all of these sources are tied together after the switches. On a boat, the ground is also connected to neutral.

Thus, you can have the following configurations.

1. The generator.
2. A 220v cord on either the port or stbd side (but not both).
3. Two 110v cords on either the port or stbd side.
4. One 110v cord on the port side and one 110v cord on the stbd side (different socket).

Obviously, options (1) & (2) will give you both 110v and 220v service. Options (3) & (4) will give you 220v service if the two 110v cords are out of phase.

If the two 110v cords are in phase, then you will not get 220v, however, the lines are still hot (meaning you can still get shocked), thus, I would flip the 220v breaker to off at the center bottom in that scenario. That way none of the 220v outlets in the boat will be hot, even though non functional.

One of the main design criteria of S1, S2 and S5, is that no source can (accidentally) be connected to another source, which would cause a major short. I would never have both 220v and 110v cords connected at the same time, but if you did, there is no switch combination (S1,S2 and S5) that would short them together. They could have done all of this distribution with no switches at all and just tied the L1, L2 and N directly to the plugs, and that would work as long as you only used the right combination of plugs at one time. Use the wrong combination, and poof. The only caveat to that is that you would NEVER want the generator connected with any shore power. So that would definitely require a transfer switch.

Also, while the whole boat shares a common neutral, that neutral is only connected to the appropriate source according to S1, S2 and S5. In other words, the sources are entirely isolated when not selected.

[oscarvan]

I think we are narrowing it down.

If you are using a 220v source, the flow is S5 to S1/S2 to AC breakers......The 110v breakers and 220v breakers are all part of the same bus, they are not separate.

Out of the bottom of S5 is a direct path to the "220V Distribution Panel and Bus" Out of S1 and S2 is a path to the L and R "Distribution Panel and Bus" (kinda missing on the schematic you can just see the top left corner of the left side coming down from S1)

This to me indicates that the 220V bus and the 110 buses are not connected.

So I believe that if there is 220V available S5 sends two phases to the 220V bus, and a single phase each up to S1 and S2 which in the 220V position send it to the respective 110V buses.

If there is (only) two times 110V available S1 and S2 are positioned accordingly, and there is no path back down to S5 and thus no path to the 220V distribution panel and bus.

I'll be on the boat this week to replace a battery bank and the mighty multi meter will tell. Since I don't have 120V/50A available I'll unplug the whole thing and use the continuity beeper.

On edit: Just received a blueprint of the AC distribution. It clearly shows the L1, L2 and 220V breakers/buses being separate, and states the feed for the 220V breakers is "from S5" If you pm me an email address I'll send it to you.

[oscarvan]

The mighty multi meter has spoken.

The S1 and S2 distribution buses are NOT connected to the 220V bus in any way except when The S1 and S2 Selectors are in the 220/110 position.

So when there's 240V available you select it on S5 which feeds the 220V bus AND you place the S1 and S2 selectors in the 220/110 position. Then there is a path from the 220V supply with one leg going through S5 to S1 and one leg going to S2. If the S1 and S2 selectors are in any position other than 220/110 there is NO path to S5 and the 220V bus.

If you connect 110V/50A from shore to the appropriate deck connectors you can power the S1 and S2 buses by selecting the appropriate side. Since they are now not in the 220/110 position there is, again, NO PATH to the 220V bus.

I find this interesting, as it means that with only 110V/50A available you had no washer dryer, but more importantly no stove....

Anywho, now for the WHY I have been pursuing this. (No, not purely for the academic argument). It's less than 10 feet from a nice spot in the generator room where I can mount an inverter, through one bulkhead to the fuse box for the Port shore power connection. I will most likely never see 110V/50A and IF it should happen I still have the SB side. Now all I have to do is tie into the cabling that runs from the fuse box into the selector panel, and re-label the S1 and S2 selector to "INV" on their "Port" position, and Bob's your Uncle!

[Photolomy]

You can’t use a Y connector?

[oscarvan]

?? To install an inverter? On deck??

[Photolomy]

?? To install an inverter? On deck??

No. You said you lose the port 110/50A connectors, but you would probably use a Y-Connector into your 220/50A anyways.