Converting from 220 volts to 110

[sailcrazy]

sorry-wrong button. And yes, the Power (watts) need to be considered. Power=Volts x Amps. And wire size is predicated on amp draw. So if your "thing" is rated at 1200 watts, using 120v power that requires 10amps. If, instead, you're using 240v power, that requires only 5 amps.....half the amperage, and half(or so) the wire size to safely carry wothout overheating due to resistance. That's why a boat wired for 230v (european power) needs to look at rewiring if its going to repower with 120v power and carry the same electrical wattage load....it needs bigger wire diameter to carry the added amp load without overheating.

[Catalysis]

My apologies if this has been covered already but why not route the shorepower supply through a victron auto-isolation transformer (or similar) then all you need to manage is cycle difference ? Added benefit of no reverse polarity or galvanic issues.


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[DotDun]

Originally Posted by sailcrazy

Based on what I've been told....do NOT use the US 220v (a 4 wire system, 110, 110, neutral, ground)) into a European 230v (a 3 wire system, 230v, nuetral, and ground) by bypassing the neutral wire in the US 220v system. By doing that you are using the ground wire for return current and not for the safety purpose it was/is intended for. Yes....it will work, but if there is a fault/short in the system......it's called FIRE! While the cycle difference needs to be addressed(motors-yes, resistance appliances-no, electronics-??) if the marina can not supply you with a 230v (or 240v) 3-wire supply, then you need to use a transformer to convert the 120v (3-wire) to 240v(3 wire) to use.....and keep the ground wire for safety-as it was intended.

It's reasonable to caution against using US 240v split phase into a EU 230v boat, but the condition you describe is not correct. The danger is someone screwing up the connections to the proper wires, as when done properly, the US ground wire would not be the return path for the EU wired system, the return path is the US L1/L2 (as that's where the 240v potential lies). The ground wire would still function as a safety wire, the difference being it would not be at neutral potential. This would only matter in EU appliances that are expecting neutral and ground to be the same potential, and that type of appliance design has not been used for many years. If the EU appliance has the 2 prong plug and plastic case, it implies internal shielding from the case and it wouldn't care that neutral and ground are at different potential. It's the older metal case appliances (if anyone remembers such things) that *could* be a problem. In reality, there is more protection with this design as IF either side of the circuit, being EU L/N or US L1/L2 (whatever you PoV), touches ground, it'll blow the circuit breaker, which is the job of the ground safety wire.

So, if wired correctly AND the appliance is capable of operation on the different frequency, connecting a EU 230v to US 240v split phase works fine.

[smac999]

Originally Posted by Cadence

Don't think I got an answer as to whether or not Europe was single or three phase. The reason for posing the question was going back to someone's question on polarity at a marina. Single phase your neutral and ground will be the same three phase it will not.

the euro 230v is single phase. their 3 phase would be 400 or somewhere around there.

it is a bit different because it's only 3 wires. 230 only. a hot line, a grounded conductor, and ground. so the 230 is between the line and grounded conducter

us the 4 wire, the 240 is between line and line and the ground and grounded conductor is the mid point. if you take the 2 hots to make the 240. neither is a grounded line.

the euro 3 wire 230 is the same as the US 110v. 3 wires. line, grounded conductor, ground.

[Cadence]

Originally Posted by smac999

the euro 230v is single phase. their 3 phase would be 400 or somewhere around there.

it is a bit different because it's only 3 wires. 230 only. a hot line, a grounded conductor, and ground. so the 230 is between the line and grounded conducter

us the 4 wire, the 240 is between line and line and the ground and grounded conductor is the mid point. if you take the 2 hots to make the 240. neither is a grounded line.

the euro 3 wire 230 is the same as the US 110v. 3 wires. line, grounded conductor, ground.

Thanks for the info.. Now I can tell what is going on with boats wired for one or the other. I wonder how many people have smoked their 110 equipment?