loader image

Cumulative effects of leakage current and Polarity Testing Devices

The term “leakage current (in installations)” refers to the current in a circuit which, in the absence of damage, flows to earth or to extraneous-conductive-parts.

In all electrical installations, there will generally be some current that will flow through the protective earth conductor and is referred to as earth leakage current. This leakage current, commonly comes from the insulation surrounding conductors and, in the filters, protecting electronic equipment installed on the Boat or Recreation Vehicle (RV).
While this may not seem like a problem for a single boat or RV, there is a concern for large Marinas or RV parks. There will be a cumulative effect due to having long runs for the earthing conductors. The longer run of the earthing conductor will increase the resistance due to its length and this increase will cause more leakage current to flow. Most RCDs* (or GFCIs**) manufacturers recommend that earthing conductors be limited to a maximum length of 76.2 m (250 feet) for this reason.

It is now a requirement that boats and RVs, have a method to confirm polarity is correct, before allowing power to be connected via an extension lead. If most polarity testing devices fitted to boats and RVs are monitoring Devices, they will each continually place a current draw to the earth conductor (<2mA). The cumulative effect of these devices will increase the amount of leakage current to the protective earth and can cause unnecessary and intermittent tripping. In extreme cases, it can cause a rise in voltage on accessible conductive parts within the boat or RV.
ESHORE is the only product on the market that does not continually allow current to be pass through the protective earth, due to its momentary polarity test making it suitable in large Marinas and RV Parks.

* Residual Current Device
** Ground Fault Current Interrupters