Wiring a Galvanic Isolator

[sideyb]

Hello Everyone,

Hopefully everyone is having a delightful round of Holidays and is healthy with friends and family.

I have a question about 120v AC wiring and how the shore connection is wired to the galvanic isolator.

When I look at any basic wiring diagram of how to wire a shore connection with the galvanic isolator in line I find something like the following, from Calder's book:

http://i.imgur.com/xJA6o43.jpg

I understand the logic behind the actual wiring schematic but I have a practical question about how to actually wire it.

1. Do I purchase 2 wire (hot and neutral) to go from the shore power inlet directly to the circuit breaker and then to the main AC panel. Then, run an individual ground wire from the shore power to the galvanic isolator and then to the main ground. Specifically, is the ground wire a separate insulated wire not in the same sheath as the hot and neutral wire?

OR

2. Do I buy three wire, remove the sheathing from the three wire to the length of the ground connection of the galvanic isolator, then to the AC main breaker and then to the panel shared ground AND THEN to the main shared AC ground.

Basically I am trying to figure out how people run three wire without removing the ground wire from the sheathing. I assume this is either done by running a separate ground wire, removing part of the sheathing, and/or running the three wire in its entirety to the main panel.

I would think that it would be option 1, I just can't find any pictures of what people have done. I am a first time poster here and have searched the forums.

Hopefully this is clear, let me know if you need me to clarify.

Thanks!

Ben

[smac999]

run 3 conductor. put the isolator at either the shore plug end, or near the panel. and remove sheath as needed. you shouldn't need to remove much as the isloater should be close to one of the ends.

[FlyingCloud1937]

Ideally, You would use AC boat-cable/Safety Wire.

Safety Wire is 3 wires laid in a jacket, preferably 105c rated. Safety Wire is laid, Line-Safety-Neutral, in flat boat cable. In round, same three wires twisted. We won't go into the dogma of why it's laid the way it is.

This is a current job under re-wire.


Notice the 2, green safety wires exiting before they enter the panel.

This boat has 2 Shore Power Inlets, one Forward, and Second Aft. They are the shore side Galvanic Isolator side Safety Wires.

A separate green Safety Wire will then lead to the Ship Side AC Bus in the Panel, from the Galvanic Isolator.

So in answer to your question, run three wire from shore side to Panel/Galvanic Isolator, then bring the Ship Side back to the Galvanic Isolator.

Lloyd





The

Originally Posted by sideyb

Hello Everyone,

Hopefully everyone is having a delightful round of Holidays and is healthy with friends and family.

I have a question about 120v AC wiring and how the shore connection is wired to the galvanic isolator.

When I look at any basic wiring diagram of how to wire a shore connection with the galvanic isolator in line I find something like the following, from Calder's book:

http://i.imgur.com/xJA6o43.jpg

I understand the logic behind the actual wiring schematic but I have a practical question about how to actually wire it.

1. Do I purchase 2 wire (hot and neutral) to go from the shore power inlet directly to the circuit breaker and then to the main AC panel. Then, run an individual ground wire from the shore power to the galvanic isolator and then to the main ground. Specifically, is the ground wire a separate insulated wire not in the same sheath as the hot and neutral wire?

OR

2. Do I buy three wire, remove the sheathing from the three wire to the length of the ground connection of the galvanic isolator, then to the AC main breaker and then to the panel shared ground AND THEN to the main shared AC ground.

Basically I am trying to figure out how people run three wire without removing the ground wire from the sheathing. I assume this is either done by running a separate ground wire, removing part of the sheathing, and/or running the three wire in its entirety to the main panel.

I would think that it would be option 1, I just can't find any pictures of what people have done. I am a first time poster here and have searched the forums.

Hopefully this is clear, let me know if you need me to clarify.

Thanks!

Ben

[AnchorageGuy]

Maybe it's just me, probably, but I'm not sure I understand the two previous posts. The green wire from your shore power outlet connections should go to the proper input side of the isolator. If you have two panels or two shore power connections, you will need an isolator capable of handling two. Then another green wire should run from the output side of the isolator to the green buss on your panel. This puts the isolator between the shore power and the boats systems. Chuck

[psneeld]

Originally Posted by AnchorageGuy

Maybe it's just me, probably, but I'm not sure I understand the two previous posts. The green wire from your shore power outlet connections should go to the proper input side of the isolator. If you have two panels or two shore power connections, you will need an isolator capable of handling two. Then another green wire should run from the output side of the isolator to the green buss on your panel. This puts the isolator between the shore power and the boats systems. Chuck

agree.... the isolator is basically just an inline set of diodes between where the green wire enters your boat and where it connects to the ground buss.

[autumnbreeze27]

Do you leave the isolator powered up all the time? We have one on our boat, and it would go to fault quite a bit at the dock. Now it's reliably green at the dock, but as soon as I cast off it goes to fault. So does that mean I have a leak on the DC side? (it goes fault with no AC on the boat)

[psneeld]

Originally Posted by autumnbreeze27

Do you leave the isolator powered up all the time? We have one on our boat, and it would go to fault quite a bit at the dock. Now it's reliably green at the dock, but as soon as I cast off it goes to fault. So does that mean I have a leak on the DC side? (it goes fault with no AC on the boat)

I would think yes..powered all the time you are on shore power...

Not positive but it sounds like a leak...any guidance from the manual?

[Paul Elliott]

Originally Posted by autumnbreeze27

Do you leave the isolator powered up all the time? We have one on our boat, and it would go to fault quite a bit at the dock. Now it's reliably green at the dock, but as soon as I cast off it goes to fault. So does that mean I have a leak on the DC side? (it goes fault with no AC on the boat)

What kind of isolator is this? Mine doesn't have a "DC side", or lights, and it can't be switched on or off. It just connects between shore-power ground and my boat's AC ground.

[GeoPowers]

Originally Posted by sideyb

Hello Everyone,

Hopefully everyone is having a delightful round of Holidays and is healthy with friends and family.

I have a question about 120v AC wiring and how the shore connection is wired to the galvanic isolator.

When I look at any basic wiring diagram of how to wire a shore connection with the galvanic isolator in line I find something like the following, from Calder's book:

http://i.imgur.com/xJA6o43.jpg

I understand the logic behind the actual wiring schematic but I have a practical question about how to actually wire it.

1. Do I purchase 2 wire (hot and neutral) to go from the shore power inlet directly to the circuit breaker and then to the main AC panel. Then, run an individual ground wire from the shore power to the galvanic isolator and then to the main ground. Specifically, is the ground wire a separate insulated wire not in the same sheath as the hot and neutral wire?

OR

2. Do I buy three wire, remove the sheathing from the three wire to the length of the ground connection of the galvanic isolator, then to the AC main breaker and then to the panel shared ground AND THEN to the main shared AC ground.

Basically I am trying to figure out how people run three wire without removing the ground wire from the sheathing. I assume this is either done by running a separate ground wire, removing part of the sheathing, and/or running the three wire in its entirety to the main panel.

I would think that it would be option 1, I just can't find any pictures of what people have done. I am a first time poster here and have searched the forums.

Hopefully this is clear, let me know if you need me to clarify.

Thanks!

Ben

Hi Ben,

I have (2) 30 Amp shorepower inlets that I recently rewired.

In my original set-up, I did like you surmised and took sheathed 3-wire from the shorepower inlets, ran those wires about 2-3 feet to near my two main disconnects (one breaker in two separate boxes), cut slits about 3" long in the sheathing, separated/cut the green ground wire, made the appropriate ground connections to the GI, and then ran the downstream sheathed wiring to the main disconnects, wiring them up as typical. I taped the heck out of the slits with electrical tape, and ziptied both ends of the cut sections of wiring to the block holding my GI to limit any movement. It was probably an okay/safe solution, but I never did like the looks of it.

In my recent rewire, I installed a Blue Sea main disconnect with dual 30A breakers in the same box that had two studs already set up to accept ground wiring (these being for shore side and boat side ground wiring, not one each for each circuit). Using the two studs, you can keep all your wiring "in the box" without opening up the shorepower sheathing. I thought it was a slick idea. Since a pic is worth 1000 words, here's the wiring diagram:

http://assets.bluesea.com/files/reso.../980013150.pdf

I used 10 ga green wire to/from the GI since that was the gauge I used for each 30A shorepower wire.

Hope this helps,

Frank

[goboatingnow]

Originally Posted by Paul Elliott

What kind of isolator is this? Mine doesn't have a "DC side", or lights, and it can't be switched on or off. It just connects between shore-power ground and my boat's AC ground.

ABYC compliant isolators must be either fail safe or have a fault indication system. Thats the "DC side" thats been mentioned here. Its merely a indication that either current is flowing in the earth wire or their is no voltage drop over the diodes. if you disconnect shore power and generate on board AC, ( and you really should be isolating the incoming shore circuit when you do that), some fault circuits will register it as a fault.

Again the incoming shore socket , should not be live with onboard AC generation in action.

Dave

[Scott Berg]

If you are contemplating a galvanic isolator I strongly recommend you consider one from Dairyland (DEI). Fail safe design--the best in the business.

http://dairyland.com/gi-galvanic-isolator.html

[GeoPowers]

Originally Posted by Scott Berg

If you are contemplating a galvanic isolator I strongly recommend you consider one from Dairyland (DEI). Fail safe design--the best in the business.

GI - Galvanic Isolator | Dairyland Electrical Industries

+1, I have had the Fail-Safe Plus 50/60A for a few years and am happy with it. I thought the name was a little misleading to folks not knowledgeable about GI's, though. Fail safe = ground continuity if the product fails. It doesn't mean that the GI will never stop functioning. I tested mine recently after a surge & when rewiring my shorepower connections and it was performing as it should.

[autumnbreeze27]

Our boat has a Guest Galvanic isolator. It used to run fault 90% of the time. In the course of working on the electrical system I found a indicator light wired wrong and now it's green all the time, except when we are away from shore power. Hence my question. I was troubleshooting it over Christmas and after totally dismantling the grounding system found the printout I put on the boat that said "The red fault light means that there's too much current or you're not at shore power." and I'm like "D'OH!". So I guess I solved my problem.

I don't recommend the guest, they probably don't make them anymore anyways, but I'm sure the ones above have a better warning system.

[D.D.]

DEI absolutly the best....Really knowledgible guys.... I have the 30 amp isolator and NEVER have to worry when plugged in. A fine piece of equipment and installs in minutes.

Fail-Safe Galvanic Isolators | DEI Marine | DEI Marine