Isolation Transformer

[jtalberts]

Anyone out there sporting an Isolation transformer? I purchased a couple of Charles Marine Iso-G2 units for my rehab. I got tired of worrying if my hull was corroding away and I also wanted to make sure I was stopping any stray current issues.

My question is in regards to the wiring. On the output on the Iso-G2s there is a stud to connect the ground on the case. Do I need to jump that to my neutral and then spit out a ground and neutral?

Here is the doc that shows it.

http://www.charlesindustries.com/marine ... -1_pr3.PDF

[barkleydave]

From the schematic looks like you do not split the safety ground and neutral
A galvantic isolator or isolation transformer prevents stray DC current from entering the safety ground thus helps prevent corrosion.


safe boating,

dave

[Roger2]

Dave,
An isolation transformer Has nothing to do with DC currents. It simply isolates the AC, so that a fault on shore can not flow through to your boat. There is NO physical connection of the AC conductors, only by induction in the transformer. To stop the DC stray current, you need the Ground current sensor mentioned in the instructions.

Roger

[Dougrose]

I installed an isolation transformer that was not intended for marine use. I isolated the case from the hull and connected the case to the marina ground, to pull the breaker if there was in internal short in the windings. I connected the secondary to the hot and neutral at my breaker panel, and connected the neutral to the green ground and then to the hull. It all works fine but might not pass an inspection to ABYC standards.

Figure 2 in the ISOG2 manual shows the ABYC way to hook the transformer up. Here, there is a screen around the primary winding that will intercept any shorts, and it is connected to the marina ground. It is not connected to anything else. The schematic shows the secondary connection to the breaker panel, with one side going to the breakers, and the other to neutral, ground, and hull. The stud on the case is probably intended to join the neutral, ground, and hull. This is probably the best way to wire it.

Figure 3 in the manual shows the use of a GFI to provide protection against shorts between the marina ac and the boat. This is a little more complicated and does not really provide much additional protection. I would go with Figure 2.

[jtalberts]

Charles Marine was back from Easter holiday and I was able to confirm what the drawings look like. I wanted to post answer so that the next person wouldn't be like, "So..... What happened?"

They said to jump from the neutral ouput (x2) to the grounding stud on the case. Then run a neutral and a grounding wire from the stud to their respective locations on the power terminal and grounding bus.