We have a 2022 Dufour 530 with a 12 | 5000 |220-100|100 120V Quattro. Our shore cable is 4-wire 50A, 125/250v. The boat was for three previous years docked at Nanny Cay Marina, BVI and was successfully plugged into 50A outlets there. The boat is now in a marina in Edgewater, MD, USA, and we recently changed slips in the same marina. Our first slip had a power pedestal with a 50A, 125/250v outlet. We plugged into the 50A outlet and everything worked fine. The marina electrician tells me that pedestal is wired for 240v. Our new slip has a pedestal with two 30A, 125v outlets. We have the option of plugging our 50A shore power cable into a reverse-Y adapter connected to two 30 A outlets, which the electrician tells us will be identical to the previous 50A outlet, or installing a new 50A, 125/250 outlet on the pedestal. My question is how is my 120v Quattro protected when the shore power is 240v? The main power breaker at the shore power inlet is this:
I am guessing that, although the boat is set up to plug into USA 240v power, only one leg (L1 or L2) is actually connected to the onboard power system and the other is terminated at the onboard plug or somewhere else onboard such as the main AC breaker (hence the unlabeled green light on the breaker). The fact only one leg of the main AC breaker is labeled is consistent with that guess but not necessarily conclusive. Does anyone in this forum have an explanation of how the Quattro is protected and whether it will continue to be protected if plugged into a reverse-Y 30A to 50A adapter?
P.S. - It just occured to me (I’m in Denver and don’t have immediate access to the boat) there is a shore/generator selector switch for the air conditioning. The switch only affects the A/C. So, one power leg goes to the Quattro. The other power leg connects to the A/C. Problem solved. Hope my mental odyssey helps someone else.
No this is not true. When plugged into a 50A 120/240 outlet, then L1 is connected to +120V, L2 is connected to -120v (180 deg out of phase with L1), this gives the 240V. N and E are also connected, making the 4 wires.
When you plug into the 2 x 30A 120V connectors with a Y adapter, then one socket is on L1 at +120v, the other is on L2 at -120V. The result is the same as the 50A connection to both L1&L2. onboard protection is also identical. However, if only one of L1 or L2 is connected, there may be some problems.
Thanks. You’re correct. I finally deciphered the mfr’s wiring diagram. One shore power leg goes to a selector switch also connected to the generator via the Quattro. The switch selects either shore or generator to power A/C, water maker, etc. The other shore power leg goes to the Quattro for charging batts. If shore power is connected while generator is running, Quattro is set to use the generator power for everything.
I am guessing that, although the boat is set up to plug into USA 240v power, only one leg (L1 or L2) is actually connected to the onboard power system
No this is not true. When plugged into a 50A 120/240 outlet, then L1 is connected to +120V, L2 is connected to -120v (180 deg out of phase with L1), this gives the 240V. N and E are also connected, making the 4 wires.
When you plug into the 2 x 30A 120V connectors with a Y adapter, then one socket is on L1 at +120v, the other is on L2 at -120V. The result is the same as the 50A connection to both L1&L2. onboard protection is also identical. However, if only one of L1 or L2 is connected, there may be some problems.
The marina tells me to purchase a splitter. Some research tells me there are 30A to 50A, 125/250v splitters and then there are reverse Y adapters. Is there a clear answer as to which I should purchase? I am 1,500 miles away from the boat and must have this shipped to the marina. I want to get it right the first time.
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