Originally Posted by windsweptms
FYI, the power feed from the inlet to distribution panel should be 10 feet or less using 10 gauge marine
tin coated triplex wire. Sometimes the power feed may be longer than 10 feet and will require a additional double pole breaker located at power inlet. The shorter the fun the better as we want to acheive a voltage drop under 3%. Regards, Windswept
The Main shore power Breaker provides Overcurrent Protection, as per A
If the location of the main shore power disconnect circuit breaker is in excess of 10 feet (three meters) from the shore power inlet or the electrical attachment point of a permanently installed shore power cord, additional fuses or circuit breakers shall be provided within 10 feet
(three meters) of the inlet or attachment point to the electrical system
of the boat. Measurement is made along the conductors.
are used in addition to the main shore power disconnect circuit breaker, their rating shall be such that the circuit breakers trip before the fuses open the circuit, in the event of overload. The ampere rating of the additional fuses or circuit breaker shall not be greater than 125% of the rating of the main shore power disconnect circuit breaker. For 120-volt service
, both the grounded and ungrounded current
carrying conductors shall be provided with this additional overcurrent protection.
Voltage Drop is not normally a consideration on a boat's 120VAC system.
Assuming a full capacity load of 30Amps at 120Volts, a 10 Foot (one-way) run of #10 AWG copper wire will result in a Voltage Drop of 0.7 Volts (0.6%).
It would take a 50 Ft run to generate a 3.6 Volt Drop (3%) at 30A 120V.
There’s good reasons most boatbuilders place the Shore Power Inlet in the cockpit:
- This location is generally within 10 Ft of the Main/Breaker Disconnect in the 120VAC Panel.
- This location is generally as well protected* from rain, splash & submersion, as can be found on a boat.
For these reasons, I don’t generally recommend a bow location.
* The Shore Power Inlet Location should be as protected (water & weather) as possible. Power Inlets subject to splash shall be Weather-Proof “In-Use”. These covers have a large
"boot" allowing the cord to be plugged in, with the cover closed.