Installing GFI Receptical

Steve A · Post by **Steve A** » Jul 27th, '99, 10:03

I have a gfi outlet on my dock that I plug my shoreside power into. I wanted to install a new gfi receptical (rather than a breaker) in my "first" outlet on my boat thereby making all outlets down line ground fault protected as well.When I travel to a marina it would be nice to know my outlets would still be gfi even if the marina was not.I can't seem to find which one is "first".Each outlet has only three wires leading to it. Mystery to me....Southern Lee is a CD 36 #105....84 yr model.Thanks for any info that You have to offer.....Steve

nma@interpath.com

Larry DeMers · Post by **Larry DeMers** » Jul 27th, '99, 11:59

Steve,

I am not sure I understand your question, but let me make a stab at it. The way I read this is that you must have multiple 120VAC outlets already installed, and you are trying to determine which is the first in the chain so that you can replace it with a GFI outlet instead.Ok so far? Hope so..
Well, there is no direct way to tell without getting into the wiring and poking around. You can get a feel for which may be the 1st. one by it's location relative to the service entrance/AC Breaker Panel in the boat. Usually, the electrician would wire in series, starting at the breaker panel, and working onwards from there.

Second method is more involved. Turn off the AC power by disconnecting the shore cable, and shutting off any inverter you might have.
Then get into the wiring behind the AC Breaker Panel, and follow the 120VAC line from the breaker out to the receptacles. This wil lead to the first one. Replace it with the GFI unit, and you will be protected.

Good Luck,

Larry DeMers
s/v DeLaMer
Cape Dory 30

Steve A wrote: I have a gfi outlet on my dock that I plug my shoreside power into. I wanted to install a new gfi receptical (rather than a breaker) in my "first" outlet on my boat thereby making all outlets down line ground fault protected as well.When I travel to a marina it would be nice to know my outlets would still be gfi even if the marina was not.I can't seem to find which one is "first".Each outlet has only three wires leading to it. Mystery to me....Southern Lee is a CD 36 #105....84 yr model.Thanks for any info that You have to offer.....Steve

demers@sgi.com

Chris Reinke · Post by **Chris Reinke** » Jul 27th, '99, 13:49

Steve - Unfortunately the solution is not as simple as saying the "first" is on the port side bulkhead. The only true test, and safest, will involve checking for continuity to and from each outlet. You must first ensure a safe operating environment by disconnecting all sources of power (shore cable, inverters, generators). You must then follow the connection from the shore power connection (mine is located on the aft port side) to the service panel and onward to each outlet. The use of a mutli-meter with a continuity tester and jumper wires is the only true way of establishing your wiring configuration. It is possible, although unlikely, that a hidden connection exists which a simple viewing of each panel would not disclose.

I would recommend that you create a wiring schematic as you proceed with your investigations so that future problems might be easily determined.

Steve A wrote: I have a gfi outlet on my dock that I plug my shoreside power into. I wanted to install a new gfi receptical (rather than a breaker) in my "first" outlet on my boat thereby making all outlets down line ground fault protected as well.When I travel to a marina it would be nice to know my outlets would still be gfi even if the marina was not.I can't seem to find which one is "first".Each outlet has only three wires leading to it. Mystery to me....Southern Lee is a CD 36 #105....84 yr model.Thanks for any info that You have to offer.....Steve

Russell · Post by **Russell** » Jul 27th, '99, 15:27

In which case, there is no "first" outlet. Of course, you can rewire to make sure that there is a first.

slaume · Post by **slaume** » Oct 3rd, '05, 06:31

Okay so I am getting ready to move into a slip for the winter and hook up to shore power for the first time. When I was surveyed last year the surveyor recommended installing a GFI to my AC circuit. The previous survey four years earlier had made the same recommendation! I had gone to the boat, GFI outlet in hand last winter and pulled the nearest outlet to the panel planning to do a simple installation. Well there was only one set of wires feeding the outlet so I stuffed it back in and forgot about it. Now that I am actually planning to use this system I figured I had best address the ground fault issue. My outlets are all (3) fed individually. The grounds and neutrals both go to their respective buss bars. The hot wire leaves the breaker as a single wire and disappears behind the hull liner. There has to be a hidden connection some where because it emerges at each outlet again as a single wire. Anyone know how Cape Dory might have connected three hot wires to one some where out of sight? Right now this is the only AC circuit that is working on the boat. There was a hot water heater that is no longer on the boat. One of the PO had removed it and guess what? The breaker is still in the panel the feed wire was connected and the water heater end was just cut off and dangling around back in the cockpit locker! Yikes!! I unhooked it from the breaker. This might be some thing to be checked if anyone has AC equipment that has been removed. Okay, back to my original concern. Given my situation do I just go ahead and instal three GFI recpticals and be done with it or is there a better way to deal with this? I may go to the electrical supply house and ask about a 30 AMP GFI unit that can be installed before the panel. If any of you have done this, where have you put it? It seems like it would end up in the cockpit locker. At least these connections are easier to make than that *&$% sanitation hose, Steve.

Oswego John · Post by **Oswego John** » Oct 3rd, '05, 09:39

Steve,
You might consider installing a GFI circuit breaker in the panel.

Hey Larry, it's great to hear from you again.

O J

Leo CD33 · Post by **Leo CD33** » Oct 3rd, '05, 11:02

Steve A, Steve L,

The least expensive method of adding GFI protection is a GFI receptacle in the ‘first’ receptacle box, replacing the normal duplex receptacle.

In both of your situations it sounds like a connector box or connector junction (of some sort) is hidden from view – which sounds abnormal. However most of our boats were manufactured when the ABYC codes were volunteer compliance, and applied very loose at that. I know my 1977 CD30K had more then a few electrical nightmares that required attention. Ex: All 12 VDC ground wires were in a wirenut / solder / tristed glob, etc., etc. (i.e. Cape Dory was also ‘loose’ in application.) Also, I believe, my CD30K did not come from the factory with AC Shore Power (ACSP) available. It was an add-on my who knows? And of what quality?

All the 120 VAC connections should be in some form of electrical ‘box’ – Junction box or receptacle box, etc. Personally I would want to chase these cables out to insure all connections are in a box. You may find that it is buried, being ‘impossible to access.

In either case the GFI receptacle method will not work. You will have to install a GFI breaker ‘Main Breaker’ with a small panel for it. The ACSP input cable from the pier (via the 3-pronged plug) would go to it first, and then its output would be connected to the downstream AC ‘Load circuit breakers’ or fuses. This connection is rather exacting, if you do not feel comfortable with it hire a marine electrician.
- Considering the negative ramifications, it may be money well spent

A close friend installed his own ACSP on a CD30C – without knowing it, he has bypassed the GFI function.

I second Chris’ recommendation ‘create a wiring schematic as you proceed’.

Hi Larry

Sailing Note: RA and I had a GREAT sail yesterday, short, but pleasant. RA even thanked me on the boat AND when we arrived home!!

Fair Winds,
Leo MacDonald
S/V Evening Light
Pine Isl. Bay, Groton, CT

Parfait's Provider · Post by **Parfait's Provider** » Oct 3rd, '05, 12:33

I can't imagine that CD ran separate AC wiring from each outlet to the panel, given that they didn't put any outlets on the starboard side, but stranger things have happened.

Parfait has GFI in the head outlet and I suppose it only protects that outlet. It was added by the PO as was the outlet in the engine compartment for the battery charger. There is only one cable coming into Parfait's panel for the outlets, but I don't know where the junction box might be if they didn't join at an outlet.

Hello Larry! Nice to "see" you again!

Andy Denmark · Post by **Andy Denmark** » Oct 3rd, '05, 15:12

Aren't there any EE's on this board? It matters not what position in line a GFCI receptacle is installed (AC circuits, remember?) except that it is installed somewhere in the line and then it protects all of them equally. AC does not flow downhill (or downline either). If you don't believe this then give it a try and you'll find that any receptacle in the line will trip the GFCI if the device plugged into it is faulty.

I have found that most home vintage panel mounted GFCI breakers are highly unreliable and would not rely on any important circuit (like an AC bilge pump) to protect the boat.
________
Hotels in mexico

Parfait's Provider · Post by **Parfait's Provider** » Oct 3rd, '05, 15:31

Begging your pardon, but a GFI is a breaker with a current sensor that detects a current imbalance in the order of milliamperes between the hot and neutral leads. It can isolate the integral sockets and any downstream from the mains, but I'll be a monkey's uncle if it can isolate any that are closer to the shore power than itself. How would it even detect an imbalance upstream?

Please explain.

Thanks.

bottomscraper · Post by **bottomscraper** » Oct 3rd, '05, 18:10

Ken is correct you want the GFI outlet as first in the chain. Also make sure that you hook up the correct set of connections. The GFI outlet will have a "load" side and a "supply" side. The load side feeds the other outlets, the supply side goes to the panel. If you hook it up wrong it will appear to work but the first outlet will not be protected!

On Mahalo there is a GFI outlet in the galley. I have assumed that it feeds the others. (Now I will check!) There is a second GFI outlet for the battery charger.

slaume · Post by **slaume** » Oct 3rd, '05, 19:53

I have dealt with GFI circuts in house wiring and it is always the first in line that protects the rest. On my CD-30 you can feel the wires going into the back of the boxes without even removing the covers or pulling the receptical. Just reach around back and feel, three wires in and nothing coming back out so you can not rely on one GFI outlet to protect the rest. I did open mine up to look just to make sure but you can feel the wires. There may be a lot of boats out there with only one protected outlet. My boat is a 1984 model. This is the year for me to deal with wiring. I found that one of those nice brass reading lights had been turned around enough times to grind away the insulation and short it on the light body. There is really nothing to keep you from turning them around and round untill that happens. I will be pulling them all to check for shorts before they happen. I was lucky to notice the breaker pop when I adjusted the lamp. It could have shorted completely and I may not have known where to begin to look. Now if I could just find out where they tied all those hot wires together on the AC side, Steve.

Andy Denmark · Post by **Andy Denmark** » Oct 3rd, '05, 22:45

It's been awhile since I've done this but I'll test this again tomorrow on both my boats as one has a GFCI receptical as "first" in line and the other has GFCI midway in a chain of four recepticals.

From a past test of the AC power systems, using the "test" button on either of these GFCI circuits results in power going off at all the other recepticals in the circuit whatever their location in the string. None of these are wired individually to the main AC panel but are chained together.

I'll report back with my findings as this could be dangerous not to know for certain.
________
Ferrari 158

Oswego John · Post by **Oswego John** » Oct 4th, '05, 00:45

Rich,

Am I ever glad that you responded as you did. I was very hesitant in sticking my nose into a discussion between two members of this board, each of whom I admire and respect for their contributions. In my opinion, Ken wins this round.

To add to the discussion, it is recommended to have no more than four receptacles on any given ground fault protected circuit. (This isn't etched in stone.) It's a safety policy.

Another thing that a GFI receptacle doesn't do is give overcurrent protection as a fuse or circuit breaker does. I was surprised to learn that many people live under the assumption that it did.

What does a GFI do and how does it work? I'll try to give an oversimplified answer, using abstract figures for demonstration purposes only.

A large 10 amp electric drill motor is plugged into a ground fault protected receptacle that is fused for 15 amps. When the drill is activated, the starting current is higher than 15 amps and the circuit breaker/fuse will kick out or blow. That's how overcurrent protection works.

Another smaller, metal framed drill that draws only 4 amps is plugged into the same circuit. While in use, this drill developes an internal short circuit and the field wiring shorts out to the grounded frame. This short creates two parallel paths for the hot wire to complete the circuit.

If the drill isn't properly grounded (third wire on cord and receptacle), the hot wire sends some amps back to home via the white neutral and also some of the amps return by passing through your hand and body to ground.

If the drill uses 4 amps, there will be 4 amps travelling through the hot side of the GFI and into the drill. Since there is a short in the drill, some of the four amps will return via the ground wire (1 amp) and the balance will return on the neutral wire (3 amps). The GFI senses that the full 4 amps isn't returning on the neutral, that there is an imbalance, and will instantly kick out, preventing serious shock to the user. That is 4 amps passing through the hot side of the GFI to the drill and only 3 amps returning back through the neutral side of the GFI.

All this sounds wonderful on paper. However, I can't count how many GFIs I have seen that were hooked up improperly by well meaning DIYers. Consequently, if they aren't hooked up properly, they offer no protection.

This is as good a time as any to mention the following.. I realize that I should have mentioned it right away after I read it. What I'm referring to is that a while back, one of the contributors mentioned that he never took chances and made it a habit to always push the test button on a GFI before he used it to make sure that it was operating okay.

When the test button is pressed, the GFI will kick out. The bad news is that it will kick out when the button is pressed, whether it is wired properly or not. If it isn't known for sure that the circuit is wired properly or not, this test could place a person under a false sense of security thinking that the circuit is protected for ground fault when it may, in fact , lack this protection.

So what type of GFI do you guys use, thermal or magnetic trip?
O J

PS: I wrote this earlier tonight but it wasn't quite finished. I put it on the back burner for later because the football game was on. (Carolina beat Green Bay). I should have known that other comments had come in in the meantime, but I couldn't read them first because I didn't want to lose what I had already typed. I bet that you computer sharpies know how to get around that.
O J

Parfait's Provider · Post by **Parfait's Provider** » Oct 4th, '05, 09:54

Andy,

I'll bet that when you hit the test button for the first in line the other GFI doesn't trip, but when you hit the test button for the downstream GFI they both trip. This speaks well of the upstream GFI and/or poorly of the downstream GFI which isn't tripping soon enough to keep the upstream GFI from tripping. The GFIs should be very fast as they are intended to reduce the chance of electrocution, but I think they take 50 milliseconds or so.

Please excuse my engineer overriding my diplomat last night; you are high on my list of people I respect.

The Cape Dory Board