T&T: 30A/50A y adapters

[Peter Bennett]

Saturday, July 8, 2006, 8:03:35 AM, Ron wrote:

RR> I hope that Arild will comment because the issue of 240 vs. 120V is involved
RR> as well, *I think.* I ironically, I'm using a dumb splitter to connect a 50
RR> amp cable to my 30 amp inlet (converting to 50 amp service in-progress.) I
RR> have noted that I have a little more "headroom" than an ordinary 30 amp 
RR> cable. Larger gauge and more available amps.

In this case, since the shore 50 Amp outlet is protected by 50 Amp breakers, you can draw up to 50 amps without tripping the breaker - but since the boat's power inlet is only rated for 30 amp, you should limit yourself to that current.

RR> I *think* that if you use 240V service, you only have 30 amps available. Not
RR> sure if you need 125V whether or not you can draw 50 amps.

The original question involved splitting the boat's 50A 240V cable to plug into two 30A 120V outlets on the dock.  Since the dock outlets will be protected by 30A breakers, you are limited to 30A 20V from each outlet. Unless the two outlets are on the same phase, you will have 30A 240 (or 208) volts available, rather than the 50A 240V you would have using the 50A outlet.

If you are unlucky, and plug into two outlets that are the same phase, you'll still have 2 x 30A/120V, but won't have 240V between the two hot wires.

RR> Ron Rogers




-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Lien Hwa 28 (AKA Polaris 30) "Sea Spray"
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