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Old 18-06-2018, 14:10   #1
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Where to locate Galvanic Isolator

It was suggested that I install a Galvanic Isolator. The one I purchased is the ProMarine FS30. This unit does not have a fan nor any operational indicators.

I would like to mount this behind the main power panel. It has easier access and better protection than is available aft where the power plug is located. There is also a good amount of space behind that panel - about 12" x 12" x 16"

Has anyone else mounted a similar device behind the power panel?

Does this isolator generate a lot of heat while in operation?
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Old 18-06-2018, 15:44   #2
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Where to locate Galvanic Isolator

Mine is mounted behind the power panel. No idea how long it has been there.
I donít think they get hot at all, havenít noticed any heat anyway
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Old 18-06-2018, 15:49   #3
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Re: Where to locate Galvanic Isolator

Manual only states the following . . . .

"Professional Mariner would also recommend that you place your Galvanic Isolator

in a dry, ventilated area."
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Old 18-06-2018, 15:57   #4
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Re: Where to locate Galvanic Isolator

I've got my isolator next to the charger/inverter, near the power panel. A dry location is good. There should be virtually no heat generated except perhaps during ground fault conditions (which we hope will be never). Just make sure that there are no other connections to the ground wire between the isolator and the shore-power plug.
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Old 18-06-2018, 17:31   #5
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Re: Where to locate Galvanic Isolator

What is the difference in purpose and effectiveness between a Galvanic Isolator and an Isolation Transformer?

I put in a Victron Isolation Transformer, in my steel boat, but honestly don't know if I could have gone with just an isolator??

How do they differ in purpose?
https://www.victronenergy.com/isolation-transformers

Positioning for both seems to be the same, but the transformer does get hot

"The isolator is installed directly behind your boat's 230V connection. The forward voltage from the galvanic isolator is higher than the potential difference between metals. As a result, this voltage will not allow conduction and as such, the galvanic isolator will prevent any electrolytic current. However, if there is a (higher) error voltage in the AC circuit, the diodes will allow current through and the residual-current device will break the circuit"
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Old 18-06-2018, 17:38   #6
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Re: Where to locate Galvanic Isolator

Found my answer
https://shop.pkys.com/Isolation-Tran...able_b_37.html
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Old 18-06-2018, 19:27   #7
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Re: Where to locate Galvanic Isolator

Thanks for the replies! I'm going to mount it behind the power panel.
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Old 19-06-2018, 10:29   #8
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Re: Where to locate Galvanic Isolator

Quote:
Originally Posted by Pelagic View Post
What is the difference in purpose and effectiveness between a Galvanic Isolator and an Isolation Transformer?

I put in a Victron Isolation Transformer, in my steel boat, but honestly don't know if I could have gone with just an isolator??

How do they differ in purpose?
https://www.victronenergy.com/isolation-transformers

Positioning for both seems to be the same, but the transformer does get hot

"The isolator is installed directly behind your boat's 230V connection. The forward voltage from the galvanic isolator is higher than the potential difference between metals. As a result, this voltage will not allow conduction and as such, the galvanic isolator will prevent any electrolytic current. However, if there is a (higher) error voltage in the AC circuit, the diodes will allow current through and the residual-current device will break the circuit"
You have made the best choice. Isolation Transformers actually isolate you from shore ground by breaking the physical connection and transferring power through a magnetic field. Isolation Transformers "Isolate" you from AC & DC stray currents and help prevent electrical shock hazards.
Galvanic Isolators don't actually "Isolate" you from anything. What they do is block DC stray current. They do nothing for AC stray current and do not prevent shock hazards. Galvanic Isolators are prone to failure and most on the market do not any any indication that they have failed. You can have a Galvanic Isolator plugged into your system and not have any idea if it is actually working. In my book Galvanic Isolators are a waste of money, take the amount that it costs and apply it towards a good Isolation Transformer.
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Old 19-06-2018, 10:46   #9
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Re: Where to locate Galvanic Isolator

Quote:
Originally Posted by Pelagic View Post
What is the difference in purpose and effectiveness between a Galvanic Isolator and an Isolation Transformer?

I put in a Victron Isolation Transformer, in my steel boat, but honestly don't know if I could have gone with just an isolator??

How do they differ in purpose?
https://www.victronenergy.com/isolation-transformers

Positioning for both seems to be the same, but the transformer does get hot

"The isolator is installed directly behind your boat's 230V connection. The forward voltage from the galvanic isolator is higher than the potential difference between metals. As a result, this voltage will not allow conduction and as such, the galvanic isolator will prevent any electrolytic current. However, if there is a (higher) error voltage in the AC circuit, the diodes will allow current through and the residual-current device will break the circuit"

Dear Pelagic,
The information you found at the isolation transformer manufacturer's website is not true. An isolation transformer does not and cannot provide the safety function provided by a galvanic isolator. If you install an isolation transformer inside your boat you "must" leave intact the connection of the shore power grounding conductor (green wire) to your boats underwater metals bonding bus to be safe and to be in compliance with safety agency requirements. You "should" connect the shore power grounding conductor through a galvanic isolator to your underwater metals bonding bus if you want to protect your underwater metals from corrosion.
Safety is not optional but protecting your underwater metals is optional and highly recommended and could be provided only by having a galvanic isolator.

Why should you believe me?
You should believe me because I can increase your level of understanding by answering and explaining my answers to your questions and your friends questions, and your friends maybe experts in the field of electrical safety and galvanic corrosion.
Have a nice day, and be very careful what you recommend and very careful with any DIY electrical work on board.
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Old 19-06-2018, 11:24   #10
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Re: Where to locate Galvanic Isolator

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Originally Posted by Ahmet Erkan View Post
Dear Pelagic,
The information you found at the isolation transformer manufacturer's website is not true. An isolation transformer does not and cannot provide the safety function provided by a galvanic isolator. If you install an isolation transformer inside your boat you "must" leave intact the connection of the shore power grounding conductor (green wire) to your boats underwater metals bonding bus to be safe and to be in compliance with safety agency requirements. You "should" connect the shore power grounding conductor through a galvanic isolator to your underwater metals bonding bus if you want to protect your underwater metals from corrosion.
Safety is not optional but protecting your underwater metals is optional and highly recommended and could be provided only by having a galvanic isolator.

Why should you believe me?
You should believe me because I can increase your level of understanding by answering and explaining my answers to your questions and your friends questions, and your friends maybe experts in the field of electrical safety and galvanic corrosion.
Have a nice day, and be very careful what you recommend and very careful with any DIY electrical work on board.
Mr. Erkan,

You are wrong about leaving the ground connection between the shore the the metal boat. The shore ground connection connects to the shield within the transformer and does not physically connect to the boat, thus you have actual "isolation". The case of the transformer is grounded to the boat, but the case is NOT connected internally to the shield. If you connect the shore ground to any place on the boat other then the transformer shield you defeat the purpose of the transformer.
I am an electrical engineer and have designed isolation transformers for both the marine environment and hospitals. You need to go back and study your electrical basics when it comes to metal corrosion and electrical hazards protection in a marine environment.
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Old 19-06-2018, 11:45   #11
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Re: Where to locate Galvanic Isolator

I think he may be thinking of a simple transformer and not the modern power isolation transformers for marine use.

I any case I would read the manufacturers specifications/instruction and double check any unit installed to make sure it provides total isolation and not a limited one. But that is me and my funny quirk with water and electricity....
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Old 19-06-2018, 12:38   #12
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Re: Where to locate Galvanic Isolator

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I think he may be thinking of a simple transformer and not the modern power isolation transformers for marine use.
Yes, the Peter Kennedy article I linked to in post #6 spoke a little about Step-up and down transformer, was a bit confusing as to the primary function.

My Victron Isolation does not do that, it only Isolates shore power and is:
230v In / 230v out.

Wiring instructions are quite clear. You do not ground the shore power cable.
Personally, I hate shore power plugs on deck as they are bulky and UV and Corrosion prone to failures.

I replaced the plug with a waterproof terminal box underneath one of the engine room dorade vents and connect the shore cable's 3 wires to Isolation Transformer there.
This way I can always see the condition of the connection inside the engine room and it is vompletely protected from the weather.
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Old 19-06-2018, 12:50   #13
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Re: Where to locate Galvanic Isolator

Quote:
Originally Posted by Pelagic View Post
Yes, the Peter Kennedy article I linked to in post #6 spoke a little about Step-up and down transformer, was a bit confusing as to the primary function.
Pelagic,

The Step Up/Down would be for say 120VAC to 220VAC or vice-versa. Typically when global cruising. But a lot of the Isolation transformers can do the same thing just have to adjust jumpers under the terminal cover.
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Old 19-06-2018, 14:10   #14
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Re: Where to locate Galvanic Isolator

Quote:
Originally Posted by Sailorlou View Post
Mr. Erkan,

You are wrong about leaving the ground connection between the shore the the metal boat. The shore ground connection connects to the shield within the transformer and does not physically connect to the boat, thus you have actual "isolation". The case of the transformer is grounded to the boat, but the case is NOT connected internally to the shield. If you connect the shore ground to any place on the boat other then the transformer shield you defeat the purpose of the transformer.
I am an electrical engineer and have designed isolation transformers for both the marine environment and hospitals. You need to go back and study your electrical basics when it comes to metal corrosion and electrical hazards protection in a marine environment.

Mr. Sailorlou and supporters of Mr. Sailorlou,
This discussion is not about you or I. Electrons couldn't care less about credentials, titles or experience, electrons care only about the laws of physics. Therefore I am going to pretend I did not hear any of your arrogant chest beatings and personal attacks and focus on the technical comments and recommendations that you have made to the fellow sailors who are looking for expert advice. First of all, I am going to explain that the most unsafe action you have recommended is connecting the case (the core and metal enclosure) of the isolation transformer to the underwater metals and the bonding system of the vessel. The ungrounded conductor/s of the shore power cable have to penetrate the case of the transformer thus have an opportunity to short to the case. Since you have also recommended that the shore power grounding conductor should not be connected to the underwater metals of the vessel, a short from the ungrounded power conductor/s to the transformer case is going to energize the underwater metals and create a high voltage gradient which is going to be fatal to swimmers, divers and all living creatures around the boat, and especially so in a fresh water environment. Electronic sensors and only if they are installed and happen to be operational may prevent a fatality. Metal (steel) vessels will have a lot more opportunities to short to the ungrounded conductors of the shore power cable.

OK Mr. proud EE medical grade transformer designer, explain away the safety hazard described above and then we will continue to the next hazard.

My first safety recommendation for onboard isolation transformers is to insulate the transformer case from the boat and connect the shore power grounding (green) conductor directly to the transformer case/core.
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Old 19-06-2018, 14:21   #15
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Re: Where to locate Galvanic Isolator

Quote:
Originally Posted by Thuid View Post
Pelagic,

The Step Up/Down would be for say 120VAC to 220VAC or vice-versa. Typically when global cruising. But a lot of the Isolation transformers can do the same thing just have to adjust jumpers under the terminal cover.
I am familiar with Step up/down transformers on board Super yachts but more for tweaking between the 208V - 280V range. Heavy loads, huge equipment

Most super yachts are configured to the more globally popular European power standard, so when plugging in to US Marinas, we combined two lines of 120VAC to get 240VAC and ran it thru a Frequency convertor.

Re my own Victron Energy Isolation Transformer 7000W 230V

It does not seem to step up/down but I will check the manual.....

This description from a US retailer:

European isolation tranformer, this model does not comply with ABYC standard 11.7.1.3 regarding shield fault current but complies with*appropriate European standards* Accepts 50 or 60 Hz inputs, 230 volt only.* Toroidal wound technology for quietness and high efficiency

Soft start circuitry will ensure that the shore circuit breaker will not trip when plugged in.Aluminum enclosureInput circuit breaker
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