# Wired and Wonderful

Mike Montanaro of Cornelius, North Carolina, asks:"Don Caseys thorough and very informative article on the proper way to install shorepower on a boat (Sail, January) clarified a lot of points for me. But he says that if you touch both wires in a 12-volt DC circuit it is unlikely to cause injury. This assumes your body is the only current draw. What would happen if there
• Author:
• Updated:
Original:

Mike Montanaro of Cornelius, North Carolina, asks:

"Don Casey’s thorough and very informative article on the proper way to install shorepower on a boat (Sail, January) clarified a lot of points for me. But he says that if you touch both wires in a 12-volt DC circuit it is unlikely to cause injury. This assumes your body is the only current draw. What would happen if there was an appliance at the end of that circuit and you touched the wires while the appliance was running? Would the current draw go into the test dummy? If so, how much 12-volt current can be harmful? What would happen if multiple batteries are wired in series and the system is 24, or even 48 volts? It’s still DC, but increasing the volts increases the amp draw. I’m curious about this because someday someone, maybe even me, might see just one battery and not know there are three more behind it.

Casey also says to install the AC isolator as close to the inlet fitting as possible. I would have thought it best to put it as close to the ground plate as possible— to keep current from getting into the system. If it’s installed near the inlet fitting, hasn’t the current reached the isolator through the system, and therefore already had a chance to do its dirty deed?"

Don Casey replies:

For almost everyone, body resistance is sufficient to keep the current potential at 12 volts below harmful levels. Quadruple the voltage and you quadruple the potential current. Because we are talking about DC, or direct current, the risk to your heart rhythm remains low, although at 50 volts one can experience a painful burn.

Whether there is an energized appliance on the circuit makes no difference. The current passing through your body is determined entirely by the voltage and the resistance your body offers between your two points of contact.

Finally, locating the isolator as close as possible to the inlet fitting minimizes the potential for stray current to find its way aboard, or into the water beyond the isolator—meaning between the isolator and the shoreside connection. Stray currents do not flow to the isolator where they are stopped. If the current is not flowing through the isolator, it is not flowing anywhere in the grounding wire.

## Crowdsourcing Age-of-Sail Weather Data

Although big, multi-million-dollar projects like the Large Hadron Collider and the human genome project with their legions of PHD’s tend to grab headlines, there’s still a part of play for the “citizen scientists” of the world. Amateur birders have long contributed to an ...read more

## Ultims to Race Solo Around the World

For years now, maxi-trimarans, both solo-sailed and fully crewed, have been racing the clock on their own around the world in an effort to set ever faster records for the world’s fastest circumnavigation under sail. Back in 2000-01 there was also a no-holds-barred ...read more

## Juneteenth on the Water

Discovering Amistad and Mystic Seaport Museum have partnered to organize their third annual Juneteenth festival, featuring concerts, speakers and a reflection on the lasting legacy of racial injustice in America. Declared a National Holiday in 2021, Juneteenth celebrates the end ...read more

## New Multihulls for 2022

Lagoon 51 In keeping with many of the more recently launched models created by French multihull builder Lagoon, the Lagoon 51 is all about comfort, “en plein air,” in particular, as the French might say. Topside, a whopping 80 percent of the boat’s flybridge is given over to ...read more

## How to Spectate on the Newport Bermuda

The biannual Newport Bermuda Race starts on Friday with the first warning signal at 1 pm. Whether you’re tracking a loved one’s progress or just spectating an event that draws pros and weekend warriors alike, there are plenty of ways to stay up to watch. The starting line will ...read more

## US Sailing Strikes Gold in Hyères

After being skunked or nearly skunked at multiple Olympiads, could the US Sailing Team (USST) now under the direction of Olympic veteran Paul Cayard, be finally turning it around? If its performance at the 53rd French Olympic Week regatta in Hyères, France, where the team posted ...read more

## New York City’s Newest Fleet

120 children enrolled in Brooklyn Boatworks’ STEM and life skills-focused program launched their hand-built optimist prams on June 14 from Pier 2 in Brooklyn Bridge Park. The launch is the culmination of years of student work, with boats in process before the pandemic caused the ...read more

## Charter: Off the Beaten Path

So, you like to charter in the Caribbean with its warm waters, swaying palm trees, steady trade winds and strong rum drinks. What’s not to love? It can be easy, though, to get stuck in a rut when chartering year after year in the same place. Sure, the British Virgin Islands are ...read more