This is a memo to owners of the following boats:
Hunter 49, 50 CC, 50AC with isolation transformers.
I have a 49 wired with 220 volt input, with an isolation transformer.
I just became aware of a wiring error on my boat, which I suggest you check for.
Firstly, I will describe the problem.
On the AC inlet receptacle, it is a 125 / 250v inlet.
The inlet has the following connections:
Black, Red, White, Green.
The boat (with isolation transformer) is wired to use the black and red terminals only. This is 220 volts. This feeds the primary of the isolation transformer.
The secondary of the transformer has a center tap, which provides the 120 volt neutral.
The cable which goes from the inlet receptacle to the isolation transformer is a #6 guage 3 conductor cable, with colors black, white green.
They should be connected to the power inlet as follows;
Black - Black, White - Red, Green to Green.
On the inlet receptacle , there are 2 blades where there is a bent portion of the pin. The third blade is flat.
It is very important to ensure that the green wire actually connects to the smaller green bonding screw, and NOT , ( as was the case on my boat), onto the blade which is flat.
Here is why I believe this mistake was made at the plant.
The green grounding terminal is much smaller than the power blade inlet screws.
As the cable is 6 guage, 3 conductor, the green wire will not fit into the ground terminal as is.
For the ground wire to fit into the green grounding terminal, approximately half of the strands need to be cut out.
This is certainly not a problem electrically, as this ground wire is never going to see 50 Amps of current. Ideally, it will never see any current at all.
Here is the potential danger of having the green wire in the white position on the receptacle. The primary side of the transformer is meant to have its ground connected to an electrically floating transformer shield.
The secondary ground connects to the transformer chassis.
If there would be a breakdown of the transformer isolation shield to the chassis, then the boat ground could be shorted to the shore power 120 v neutral.
To inspect your boat, it is very simple.
Firstly, unplug your shore power cord.
Make sure your inverter and generators are both off.
Unscrew the 220v inlet receptacle from the stern. On my vessel, the screws were self tapping screws into the Fiberglas.
Carefully extract the receptacle, and gently pull the wiring . There should be internal slack in the cable to permit this.
If not, you will need to free up the cable a bit.
Looking at the back of the receptacle, ensure that the green wire connects to the green grounding screw. While you have the receptacle out, ensure that the black and white wire are well secured in their terminals. A slight pull will confirm this.
If the green is in one of the large power terminals, and not on the green lug, this must be corrected
Hunter 49, 50 CC, 50AC with isolation transformers.
I have a 49 wired with 220 volt input, with an isolation transformer.
I just became aware of a wiring error on my boat, which I suggest you check for.
Firstly, I will describe the problem.
On the AC inlet receptacle, it is a 125 / 250v inlet.
The inlet has the following connections:
Black, Red, White, Green.
The boat (with isolation transformer) is wired to use the black and red terminals only. This is 220 volts. This feeds the primary of the isolation transformer.
The secondary of the transformer has a center tap, which provides the 120 volt neutral.
The cable which goes from the inlet receptacle to the isolation transformer is a #6 guage 3 conductor cable, with colors black, white green.
They should be connected to the power inlet as follows;
Black - Black, White - Red, Green to Green.
On the inlet receptacle , there are 2 blades where there is a bent portion of the pin. The third blade is flat.
It is very important to ensure that the green wire actually connects to the smaller green bonding screw, and NOT , ( as was the case on my boat), onto the blade which is flat.
Here is why I believe this mistake was made at the plant.
The green grounding terminal is much smaller than the power blade inlet screws.
As the cable is 6 guage, 3 conductor, the green wire will not fit into the ground terminal as is.
For the ground wire to fit into the green grounding terminal, approximately half of the strands need to be cut out.
This is certainly not a problem electrically, as this ground wire is never going to see 50 Amps of current. Ideally, it will never see any current at all.
Here is the potential danger of having the green wire in the white position on the receptacle. The primary side of the transformer is meant to have its ground connected to an electrically floating transformer shield.
The secondary ground connects to the transformer chassis.
If there would be a breakdown of the transformer isolation shield to the chassis, then the boat ground could be shorted to the shore power 120 v neutral.
To inspect your boat, it is very simple.
Firstly, unplug your shore power cord.
Make sure your inverter and generators are both off.
Unscrew the 220v inlet receptacle from the stern. On my vessel, the screws were self tapping screws into the Fiberglas.
Carefully extract the receptacle, and gently pull the wiring . There should be internal slack in the cable to permit this.
If not, you will need to free up the cable a bit.
Looking at the back of the receptacle, ensure that the green wire connects to the green grounding screw. While you have the receptacle out, ensure that the black and white wire are well secured in their terminals. A slight pull will confirm this.
If the green is in one of the large power terminals, and not on the green lug, this must be corrected
