How do I measure stray current at my marina?

[Mitch]

I'm burning up zincs. 1/2 of each one (2) Every two months. How do you measure the current in the water at your boat? I read somewhere, but can't find the article, that you use a multimeter connected to the boat somehow.Thanks for the help.

 

[singpilot]

While on the high side of normal....

While that rate is on the high side of normal, it's not unusual.At least you are sure that they are working.One way to isolate the source would be to unplug your boat from the dock power (literally unplug the cord to get off of that ground source) and see if the zinc consumption rate changes.Yes, there is a way of using a sensitive multimeter to check stray current, but your marina should be the one doing the check.Keep us posted.

 

[Richard A. Marble]

How to check for stray current

shut off or disconnect your batteries. Use a multy meter using some sort of ground and place the possitive probe on metal surfaces like your engine. I do not know what to use as a ground.

 

[John Richard]

How to check

I too was using zincs so I had a buddy who is also a marine electrician down to the boat. He found that there are two galvanic isolators supplied by Hunter. This is on a 410. They were not hooked up properly. He made the connection.Then he went to the source of our shore power, turned off the power, removed the male end of the cord, and stuck the black lead into the ground. The positive lead was placed into the water. The reading was .75 volts. I told our marina management about it, but nothing was done other than to send me a letter thanking me for my concern.John Richards/v Jack's Place

 

[Don Alexander]

Quick Check

Mitch,If you suspect that your shore power is involved in the problem and you normally leave it plugged in, then you could try this - but ONLY if you are competent with things electrical. If not get a friendly Sparks to do it.On the plug you put into the dockside receptacle take the earth wire (green or green/yellow) out of the plug and insert a short length of wire. Put a multi meter set to Amps between the new wire and the earth on your shore power lead. Make sure the earth lead is continuous and not likely to come adrift as otherwise your boat and occupants will be unprotected and this could lead to injury or electrocution. You have been warned! Plug in and switch on. Check if any current is flowing. Try on both DC and AC amps. No current means no problem from this source. You could have up to 1/2 amp by the rate the zincs are disappearing.This could be because of your boat or from a neighbour's. Neighbours move and their chargers refers etc switch on and off at intervals so you might not see it immediately. If you do measure a current then at least you are on the track.Keep safe.