You need to account for both 30-amp receptacles in each slip.Here's why: Actual Load

A boat in that slip could potentially draw power from both 30-amp receptacles simultaneously.

Code Compliance

Electrical codes (like the NEC in the US) are designed to ensure safety and prevent overloads. They require you to consider the potential maximum load.

Load Diversity (Potential)

While it's possible that a boat might not always use both receptacles to their full capacity at the same time, you can't guarantee that. You need to design for the worst-case scenario.

Therefore, for each slip, you should calculate the load as if it were drawing a full 30 amps from each of the two receptacles.Important Considerations



Voltage

Make sure you're clear on the voltage of the receptacles. Most likely, they are 120V. However, some larger boats might use 240V. The voltage will affect your calculations for total power (watts).

Demand Factors (If Applicable)

Electrical codes may allow you to apply demand factors to the overall dock load if you have a large number of slips. A demand factor is a percentage that accounts for the fact that not all slips will be drawing their maximum power at the same time.

However, you should always consult with a qualified electrical engineer or inspector to determine if demand factors are permitted in your specific situation and how to apply them correctly. Demand factors are very code-dependent. Wiring and Overcurrent Protection

The wiring and overcurrent protection (circuit breakers or fuses) for the dock must be sized to handle the total calculated load, taking into account any applicable demand factors.

Grounding and Bonding

Marine environments require special attention to grounding and bonding to prevent electrical shock hazards.

Local Codes and Regulations

Always consult with your local electrical inspector and follow all applicable codes and regulations. Marine electrical work is often heavily regulated due to the increased risk of electrical shock in a wet environment.

In summary, plan for the full load of BOTH 30-amp receptacles per slip unless a qualified professional advises you otherwise and the code allows for it. Flag for review