Smartplug question

Sep 20, 2006
155
Hunter 49 Mystic CT
Have a 250/125 electrical system and have installed a 50amp smart plug The cable carried 4 wires. Red black white and green. I hooked up the three wires as per the instructions. Black white and green. I'm getting power to the boat and hear a buzzing at the electrical panel but nothing is being piped into the systems. Any one have any thoughts?

Dave
Hunter 49
 
Jan 30, 2012
1,093
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Unplug immediately. You are describing a hookup for 125 vac 30 amp.

Consult/follow instructions here.

http://www.smartplug.com/docs_misc/50AmpConnectorInstallation.pdf.

Your 250 vac 50 amp is 3 wires plus safety green for total of 4 wires not 3.

By the way you did not say whether you are doing boatside or cordside but one assumes you must be doing both. You should have 4 wires from the boatside plug to boat distribution panel. The cordside will match as well - 4 wires in the cordset not 3.

Charles
 
Last edited:
Sep 20, 2006
155
Hunter 49 Mystic CT
Thanks Charles but here's the issue The boat side has only 3 wires Hot(black) neutral (white) and Ground(green) the instructions indicate to leave the set screw alone for the forth wire (red) which i did.

I tried the cord set plug with all four wires plugged into the corresponding ports with no luck. so i'm stumped. I'm also pretty sure that buzzing i heard is the shorepower/genset relay. Is it possible I have a polarity issue?

also just checked the owners manual the power in is a 50 amp 120/240 if it makes any difference
 
Jan 30, 2012
1,093
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Understood- and not altogether a complete surprise. 250/50 amp 3 pole is (risky) old tech.

Green is not 'safety' green and is being used as a conductor instead. If it worked before you need to match colors exactly as they were before and it will work as it did before.

It is impossible to provide a clincher diagnosis from here - one needs to be onsite thus to assure the feeds are right.

The central point is that polarity and alignment of neutral is important. These must match up - so get this right - otherwise high risk of serious consequences.

Charles
 
Jun 11, 2011
1,243
Hunter 41 Lewes
Have a 250/125 electrical system and have installed a 50amp smart plug The cable carried 4 wires. Red black white and green. I hooked up the three wires as per the instructions. Black white and green. I'm getting power to the boat and hear a buzzing at the electrical panel but nothing is being piped into the systems. Any one have any thoughts? Dave Hunter 49
I don't know what you actually have but a 50 amp plug is two hot wires, black and red, one neutral, white, and one ground, green. Either the black or red wire should read 115 volts approximately to the white or green. The black and red wires should read somewhere between 208 to 240 between each other depending upon the marina's incoming electrical service. If the boat had only black white and green it was wired for a thirty amp plug at that location on the boat. I would have thought that a 49 would be a fifty amp plug but I'd really like to see some pics. Also a 49 should have an isolation transformer before the panel.
 
Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
The central point is that polarity and alignment of neutral is important. These must match up - so get this right - otherwise high risk of serious consequences.

Charles
Bingo!!!!!!!!!!!!!!!!!!!!!!
 
Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
I don't know what you actually have but a 50 amp plug is two hot wires, black and red, one neutral, white, and one ground, green. Either the black or red wire should read 115 volts approximately to the white or green. The black and red wires should read somewhere between 208 to 240 between each other depending upon the marina's incoming electrical service. If the boat had only black white and green it was wired for a thirty amp plug at that location on the boat. I would have thought that a 49 would be a fifty amp plug but I'd really like to see some pics. Also a 49 should have an isolation transformer before the panel.
There are tons of 50A 125V wired boats out there and the issue becomes wiring them for a 50A 125V/250V pedestal... 50A 125V is the old standard 50A..... Most new boats are wired for 50A 125V/250V...

A 50A 120V socket or plug will be labeled 50A - 125V

A 50A 240V socket or plug will be labeled 50A - 125/250V

These are not interchangeable but they sell adapters....
 
Jan 10, 2012
75
HUNTER 49 MARINA DEL REY
Artboas who is on this site found his 49 was miss-wired on the boat side of the plug. Mine was also miss wired. Their are only 3 wires on the boat side which in my case go to the isolation transformer, this I believe was a Hunter option. On the boat side the green wire should go to the ground lug not the neutral. If you match the plug colors with the cable all should be fine. You need to make sure that you our feeding 240 or 208 from the dock and you have a 50a 240V 120/250 plug. I don't know of any Hunter 49's that our wire for 120V.
 
Jun 11, 2011
1,243
Hunter 41 Lewes
There are tons of 50A 125V wired boats out there and the issue becomes wiring them for a 50A 125V/250V pedestal... 50A 125V is the old standard 50A..... Most new boats are wired for 50A 125V/250V... A 50A 120V socket or plug will be labeled 50A - 125V A 50A 240V socket or plug will be labeled 50A - 125/250V These are not interchangeable but they sell adapters....
Maine, it seems as though he is using a 125/250volt cord to the boat which leaves him with a red wire, L2, swinging in the breeze and it's hot. I would rather see him use the appropriate 125volt cord to the boat and use the adaptor at the pedestal. That would then make no connection to the second hot leg.
 
Jun 11, 2011
1,243
Hunter 41 Lewes
Artboas who is on this site found his 49 was miss-wired on the boat side of the plug. Mine was also miss wired. Their are only 3 wires on the boat side which in my case go to the isolation transformer, this I believe was a Hunter option. On the boat side the green wire should go to the ground lug not the neutral. If you match the plug colors with the cable all should be fine. You need to make sure that you our feeding 240 or 208 from the dock and you have a 50a 240V 120/250 plug. I don't know of any Hunter 49's that our wire for 120V.
RR the boat actually IS two hots and a ground? Because if that is the case there shouldn't be a 125volt plug anywhere. I just don't get how they can ignore the National Electrical Code when they build a boat.
 
Jun 11, 2011
1,243
Hunter 41 Lewes
Thanks Woodster. There are actually ALOT more plug configuration out there but they are not used in a marine environment. I'm still not getting how a US boat builder can ignore NEC rules. If you do not use the correct plug assembly as it relates to the voltage and amperage, eventually, someone will get hurt. It's standardized for a good reason, safety.
 
Sep 15, 2009
6,242
S2 9.2a Fairhope Al
that is actually covered in the nec

i screwed this up let me try again
 
Sep 15, 2009
6,242
S2 9.2a Fairhope Al
i found it one time but can't find it now ...any way it is covered in the code and is doable
 
Sep 15, 2009
6,242
S2 9.2a Fairhope Al
ok i don't know how to post a pdf file where one can read or open it but its under mike holt electrical code interpretation article 555 when you google it
 
Sep 20, 2006
155
Hunter 49 Mystic CT
Ok when looking at the wiring schematic of the isolation transformer, you see that as was stated, only three wires are used. The white wire appears to be playing the part of the red wire so this is what messed me up. The Isolation Transformer to the shore power plug does not use the neutral (white) Only Black Green and Red So thats my fix. I have not taken off the panel on the transformer to confirm the actual wiring but I will before moving forward, For all I know the black could be red and the white is wired for black.
 
Last edited:
Sep 20, 2006
155
Hunter 49 Mystic CT
Well that was it. I confirmed that the Isolation transformer was using the white to play the part of the red. I rewired the boat side of the smart plug to reflect this and everything worked as before. I've got a lot of juice running thru the system right now and putting a temp gun on the major bits to make sure nothing is heating up.

Thanks to all for your help and suggestions.
 
Jun 11, 2011
1,243
Hunter 41 Lewes
Ok when looking at the wiring schematic of the isolation transformer, you see that as was stated, only three wires are used. The white wire appears to be playing the part of the red wire so this is what messed me up. The Isolation Transformer to the shore power plug does not use the neutral (white) Only Black Green and Red So thats my fix. I have not taken off the panel on the transformer to confirm the actual wiring but I will before moving forward, For all I know the black could be red and the white is wired for black.

That makes sense. I know the shore neutral is not used at the isolation transformer, and that the boat neutral is derived on the secondary side. Thanks for explaining Breezin.