Shore power question

[2savage]

I am in need of 50 amps and there are four wires that are on my end. Red Black, White and Green.

The information I have is as follows:

Black = Ungrounded conductor
White = Grounded conductor
Red = Ungrounded conductor
Green = Grounded Conductor

Can some sage of electricity please enlighten me on what's going on here?

I've been dealing with house electrics and basic boat 12v for ever, and now my wife thinks I'm about to become electrocuted.

 

[rslifkin]

A 4 wire 50A connection is a 120/240V split phase connection. Wires should be as follows:

Black = L1 hot
Red = L2 hot
White = Neutral
Green = Ground

From L1 or L2 to Neutral you'll get 120v (so you get 2x 120v legs, each good for up to 50A). From L1 to L2 you'll get 240v (good for up to 50A). Using power on the 240v side reduces the remaining power available to use on each 120v leg. So a 20A load at 240v means you've got 30A left on each 120v leg.

 

[STB]

I am in need of 50 amps and there are four wires that are on my end. Red Black, White and Green.

The information I have is as follows:

Black = Ungrounded conductor
White = Grounded conductor
Red = Ungrounded conductor
Green = Grounded Conductor

Can some sage of electricity please enlighten me on what's going on here?

I've been dealing with house electrics and basic boat 12v for ever, and now my wife thinks I'm about to become electrocuted.

rslifkin explains the purpose of each wire nicely.

Just note that there is probably ~208+v from that red wire to that black wire (or vice versa). That's got a lot more kick and is a lot more dangerous than the usual household voltage. Use a no-contact tester to confirm voltage first (to check the tester). Shut everything off. And, again use the no-contact tester to confirm that everything is off. Then do whatever work needs done.

Examples of non-contact voltage testers (I don't own and have never seen either of these exact models):

https://www.homedepot.com/p/Klein-Tools-Non-Contact-Voltage-Tester-Pen-50-1000V-AC-NCVT1PR/317460355


https://www.amazon.com/KAIWEETS-Sen...tact-Flashlight/dp/B07SL4NSS1/ref=sr_1_1_sspa

Some people do work live. I have from time to time. But, it takes a lot of experience to spot hazards and do it with confidence, and even then there is always some risk. There very rarely is an actual reason to take the risk in all reality.

Most professional electrical contractors and work sites now have safety policies completely forbidding live work, except under very specific criteria where it is required, and even then under very specific protocols.

Don't work live. Make sure you aren't working live. Test without touching to make sure you aren't working live.

 

[tiltrider1]

STB is correct that when measuring from L1 to L2 you will often find 208v. You will still find 120v from L1 or L2 to neutral. Unless there is an isolation transformer installed.

So now you have just enough information to be dangerous.

 

[ranger58sb]

Unless there is an isolation transformer installed.

And if there's an isolation transformer, then the shorepower cable doesn't need neutral.

-Chris

 

[2savage]

There is an isolation box that was wired inline to the earth (green) wire for the transformer I removed. Thanks everyone for the input; I think I can now wire things up. When I get home that is. I'm currently on a ferry going from Finland to Sweden!