In general, these systems give swimmers a false sense of security. Panel includes 105 dB buzzer and contacts to trip up to four GFI circuits, $695 ( The professionally installed Dock Lifeguard detects a hot grounded dock. The battery can be tested by placing a supplied magnet against the panel is a specific location, which lights a light and causes a chirp. Powered by a 9 volt battery, the alarm, which is not very loud, emits six second chirps for 24 hours, after which the battery is dead. Detects as little as 1.7 volts differential from ground. The panel includes both LED indicating the relative strength of the field, and loud alarm, and a flashing light, from $950 ( Safe Water Systems Shock Guard 24/7 Up to four sensors, each protecting a 26-foot radius. Up to four sensors may be used to increase the area of coverage. Installation cost varies, typically from $150 to $350.ĭock Lifeguard A single sensor, properly placed, is said to protect an area about 40 feet on a side. Fixed Mount Alarmsįor fixed units, professional installation is strongly recommended, both to ensure that the unit is properly installed and to inspect all wiring for compliance with current electrical code (compliance with original code at time of construction means nothing). Ordinarily Practical Sailor tests all of the equipment we review, but for this preliminary market scan, we interviewed the manufacturers and several users, and reviewed the specifications. There is no universal standard for this type of equipment. Although several units claim to be UL certified, this appears to be in reference to their UL-compliant components. There is no UL listing for this category of products. If it is located too far from the fault or located close to a grounded, metal portion of the dock, it may not measure a voltage differential. These units simply measure the difference in voltage between the shore power ground and the water where the sensor is located. There are electric field detectors, that with various levels of rigor, detect dangerous faults. While the best policy is to stay out of the water, a lakeside dock is a kid magnet. Install a solar system on your boat, eliminating the need for shore power.This provides a barrier between the shore ground and hull ground. Install galvanic isolator in all shore power systems.Never swim in or near freshwater marinas.ĭo not swim around freshwater docks that have electrical equipment.Never swim if a portable 120-volt pump is in use. Although swimming pool electrocutions are extremely rare (all pools equipment must meet strict safety codes),Īccidents can happen.If you must swim in a saltwater marina, unplug yours and nearby boats and turn off pedestal breakers and battery switches.If theres none in the circuit, install a GFI pigtail. The seawater becomes an excellent coupler from the sailor to ground, and wet hands make a good connection to the power tool. Using power tools near freshwater or saltwater can be lethal. ![]() Never use 120 volt power tools from a tender or float, or even in a way where wet conditions can create a ground through you.If the dock is used by swimmers, install only low voltage lighting and no power outlets.In freshwater, the power gradient can extend as much as 150 feet from the fault. Move your boat at least 150 yards from any marina before entering the water to perform maintenance or to scrub the bottom.When you go for a sail, switch off the AC power breakers onboard and at the shore power pedestal and unplug the power cord.Encourage your marina to test periodically for leakage. Because current seeks the least resistant path, the preferred electrical path in freshwater is your body, while in saltwater-except in unusual circumstances (metal prosthetics, for example)-it is water. The human body is more conductive than freshwater, but less conductive than salt water. ![]() This danger is regarded as almost exclusively limited to freshwater-although no one should ever consider a saltwater marina to be free of electrocution risk. ![]() Their diaphragm is paralyzed, their swimming muscles incapacitated, and they simply sink. It is called Electric Shock Drowning (ESD).Ī victim of ESD doesn’t always appear to struggle, because they physically can’t. Every year several people die because they go swimming near a dock, a wiring fault creates an electric field in the water, and their muscles freeze. The human body runs on electricity and if you overload the nervous system with an external field, everything goes haywire.
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