The Design of Everyday Things Electrical

Electrical and electronic topics for small boats
jimh
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The Design of Everyday Things Electrical

Postby jimh » Tue Mar 31, 2020 1:46 pm

This article discusses the design of electrical connectors with regard to the gender of the connector and how it should be used.

A common practice with electrical connections is that the mating connectors are arranged in two genders, one with pins (which is usually called the male gender), and one with sockets (which is usually called the female gender). It is universal in the practice of electrical wiring that when a connector is provided in a circuit where there is a source of power, the connector attached to the side of the circuit supplying the power is a female gender, that is, it has sockets. To confirm this notion as being a common practice, one only has to look around their home at the electrical outlets for 115-VAC. The outlets are all of the female gender. The cords on appliances that plug into the outlets are all of the male gender.

It takes only the briefest moment of thought to appreciate why the connectors are arranged in this manner. If the 115-VAC power source were provided on a connector with protruding pins, there would be quite a hazard created. Accidental contact with the 115-VAC on the pins of the power outlets would be painful and dangerous, possibly fatal.

In a small boat the power distribution branch circuits carry only 12-VDC, but the same concept applies to use of male and female connectors. In circuits where there is a source of power, that portion of the circuit is provided on connectors which are female in gender. While 12-VDC may not be as much of a hazard to health as 120-VAC, contact with it can be dangerous.

A further concern is for the health of the electrical circuit itself. If you were to distribute 12-VDC on connectors with exposed pins, a short circuit could easily occur. An additional concern is that the 12-VDC voltage could come in contact with some metallic component of the boat which was not well bonded to the boat ground (or battery negative terminal). Any metal with an elevated voltage immersed in a liquid creates a galvanic corrosion situation which will begin to rapidly erode any less noble metals that are also immersed in the liquid.

For example, if a connector carrying the 12-VDC from the battery on an exposed pin were to accidently come in contact with some portion of the boat or motor, perhaps something as common as a transom mounting bolt, this component would immediate form a cathode in a galvanic corrosion circuit. The branch circuit carrying the 12-VDC may be fused with a current limiting device whose rating is too high to be tripped from this galvanic current. The result is very rapid corrosion of any less noble metals around the boat, for example the engine gear case or propeller.

For these reasons, there are simple everyday design considerations for electrical circuits regarding what gender will be used on circuits distributing power.

There is one interesting case in which a problem arises is selecting which circuit should have which gender: when both circuits provide electrical power. This can occur, for example, when connecting one battery to another. The solution to this problem is to use a genderless connector, that is, a connector that mates with itself.

A very common and well-know electrical connector used in this situation is the Anderson POWERPOLE connector. In addition to being a genderless connector, it is also a modular connector. Individual circuit connectors can be linked to there connectors to build more complex multi-pole connectors. For more information, see:

https://www.andersonpower.com/us/en/res ... sPage.html

Unfortunately, Anderson POWERPOLE connectors are not particularly useful in marine applications, as they have no seals and are not at all weatherproof.