electrical shore power question

[jviss]

YES.... even at its best it can be confusing.... and for the record, the older designated 110v has been bumped up to 120 volts, and the 220 service is now 240... and has been for several years....
But 50 amp service IS in fact 220 volt service... it is now and always will be. BUT.... you may plug into it and only get 110v from it.... depending on how the adaptor or boat/vehicle is wired.... in this case it is single phase power, but there are 2 legs of 110 power that combine to make 220... for ranges and clothes dryers.... but they can be split to create 110 volt so that half the load requirements can draw amperage from one leg, and the other half can draw from the other leg without overloading one individual circuit.....

and YES.... even at its best it can be confusing....

Despite your rather lame attempt at sarcasm, you continue to be wrong. "50 Amp service" is not "in fact" 220V Volt service, it is either 125V or 125/250V. That's what it's called. It will likely be less than the service voltage due to drops in the system, and the realities of electrical service, but that's what the rating is. As far as the two types of service go: look it up.

 

[Steve W]

Rickj, that's exactly what I'm looking to do - except to carry my own Y splitter. As soon as I've got a chance, I'll pick up that 50A Dockside to 2-30A splitter and call it a day. And to Main Sail's point, I can't give you the exact wire diameters but I know (because I installed them, I've got breakers just inside the hull where the 30A outlets come into the boat (plus isolators for each inlet) and hefty from there to the AC Panel and sufficient breakers at the panel plus what's inside the Freedom (Heart?) 2000W charger/inverter. I've had a few folks look at the set up and the consensus is that I'm sufficiently protected - actually more than sufficiently protected.

Now after all this discussion, I know I'll pick up one of those splitters and it will live on board in a locker for at least another year or so before I run into that scenario again!

Thanks for the education, everyone!

Steve

 

[Bill Roosa]

So we are ok plugging in 60 amps potential load to a 50 amp service?
If you need a 30 amp service but all the dock has is 50 amp then you need an adapter not a splitter

 

[Steve W]

I probably should have done this earlier but the attached PDF (from the WM Catalog) is are what I'm talking about which started this whole thread.

Some are saying they're splitters and I'm okay, some are saying I can't do this without frying the boat. WM calls them Adapters.

It seems to me that at this point in time, SOMEONE would have had them taken off the market if they were dangerous or didn't work as advertized which in my mind is as a "step-down" spliiter to bring two 30A power cords into the boat from a single 50A outlet.

 

[centerline]

Despite your rather lame attempt at sarcasm, you continue to be wrong. "50 Amp service" is not "in fact" 220V Volt service, it is either 125V or 125/250V. That's what it's called. It will likely be less than the service voltage due to drops in the system, and the realities of electrical service, but that's what the rating is. As far as the two types of service go: look it up.

I think its more of a description difference here.... you are correct that the textbook description would be "125/250v", but for anyone who has the ability to wire single phase power will understand what clearly what 220 or 230 or 240 or 250 volt service means.... and in context, I was explaining how the 50 amp power works... Im sorry to have offended you..
a 125/250 volt circuit is still considered a 240 volt circuit.... 220, 230, 240, 250..... its all the same only with a voltage variation that is controlled by the power company in the local area.
if you are able to understand how the power is delivered to the plug, you would then be able to understand how it can deliver only 110, 115, 120, or 125 volts to whatever unit needs the voltage reduced from whats available at the plug.....
as for a 50amp 120volt circuit, I suppose thats just a Massachusetts thing... it is so rare and unused elsewhere it is for the most part, obsolete.... but you are correct that it is possible. some boats may be wired that way occasionally, but the shore power side, not so much...... and no sarcasm intended.

 

[Maine Sail]

as for a 50amp 120volt circuit, I suppose thats just a Massachusetts thing... it is so rare and unused elsewhere it is for the most part, obsolete.... but you are correct that it is possible. some boats may be wired that way occasionally, but the shore power side, not so much...... and no sarcasm intended.

Actually the 50A 125V receptacle is not very rare at all, in marinas... 50A/125V dock pedestals are actually quite common and in older smaller marinas can still be quite popular.

The vast majority of 50A serviced boats I work on are 50A / 125V recepticals not the four wire 50A 125/250V recepticals. Marinas can generally offer both recepticals 50A 125V or 50A 125/250V, but some are 50A 125V only or 50A 125/250V only. Most newer or newly re-wired marinas opt for the pedestals to have the 50A 125/250V recepticals not the 50A 125V recepticals.

If you are at a marina with 50A 125/250V recepticals and have a 50A 125V boat, most older boats are 50A 125V, then you need an adapter to go from 50A 125/250V down to 50A 125V.... One of our local marinas switched from 50A 125V to 50A 125/250V and now the majority of 50A served boats need the adapter to get from 50A 125/250V to 50A 125V....

Kind of a PITA to have that many connections in a shore power cord but their pedestals did not have room for both 50A 125V and 50A 125/250V. Many newer large boats are coming through 50A 125/250V and you can't convert up to 50A 125/250V from a 50A 125V pedestal but you can step down to 50A 125V, so they made the move.. Many other local marinas offer only 50A 125V and it is far from "obsolete"......

 

[centerline]

:neutral:

 

[centerline]

Actually the 50A 125V receptacle is not very rare at all, in marinas... 50A/125V dock pedestals are actually quite common and in older smaller marinas can still be quite popular.

The vast majority of 50A serviced boats I work on are 50A / 125V recepticals not the four wire 50A 125/250V recepticals. Marinas can generally offer both recepticals 50A 125V or 50A 125/250V, but some are 50A 125V only or 50A 125/250V only. Most newer or newly re-wired marinas opt for the pedestals to have the 50A 125/250V recepticals not the 50A 125V recepticals.

If you are at a marina with 50A 125/250V recepticals and have a 50A 125V boat, most older boats are 50A 125V, then you need an adapter to go from 50A 125/250V down to 50A 125V.... One of our local marinas switched from 50A 125V to 50A 125/250V and now the majority of 50A served boats need the adapter to get from 50A 125/250V to 50A 125V....

Kind of a PITA to have that many connections in a shore power cord but their pedestals did not have room for both 50A 125V and 50A 125/250V. Many newer large boats are coming through 50A 125/250V and you can't convert up to 50A 125/250V from a 50A 125V pedestal but you can step down to 50A 125V, so they made the move.. Many other local marinas offer only 50A 125V and it is far from "obsolete"......

All i can do is tuck my tail and appolgize im on the west coast and although there may be some marinas here with the 50amp 125v service I am not aware of any, nor have I heard of any. its either 30amp 120 or 50amp 120/240.... but I still stand behind my explanations of how it works, even if i have misunderstood how some parts of the rest of the world does it..... ill try to do better next time

 

[jviss]

I think its more of a description difference here.... you are correct that the textbook description would be "125/250v", but for anyone who has the ability to wire single phase power will understand what clearly what 220 or 230 or 240 or 250 volt service means.... and in context, I was explaining how the 50 amp power works... Im sorry to have offended you..
a 125/250 volt circuit is still considered a 240 volt circuit.... 220, 230, 240, 250..... its all the same only with a voltage variation that is controlled by the power company in the local area.
if you are able to understand how the power is delivered to the plug, you would then be able to understand how it can deliver only 110, 115, 120, or 125 volts to whatever unit needs the voltage reduced from whats available at the plug.....
as for a 50amp 120volt circuit, I suppose thats just a Massachusetts thing... it is so rare and unused elsewhere it is for the most part, obsolete.... but you are correct that it is possible. some boats may be wired that way occasionally, but the shore power side, not so much...... and no sarcasm intended.

I interpreted your reply as if you were saying that I didn't understand this stuff, which is not the case.

I disagree with your statement "a 125/250 volt circuit is still considered a 240 volt circuit." It's not, it's a dual voltage circuit. There are 240V circuits that are not. Single-voltage 250V outlets have no white wire, only the two blacks (hot) and a ground (green wire).

In this note, when you say "if you are able to understand how the power is delivered to the plug" as if you are again saying that I don't understand how this works. What I don't understand is what you are saying in the rest of that sentence.

 

[Ron20324]

I interpreted your reply as if you were saying that I didn't understand this stuff, which is not the case....Single-voltage 250V outlets have no white wire, only the two blacks (hot) and a ground (green wire). In this note, when you say....as if you are again saying that I don't understand how this works.

Don't know where JVISS lives, but he changes from 240 volts to 250 volts in mid-stream.

As usual on these forums, people shoot from the hip, "recalling from memory" what they think is correct, and as usual, no one recalls anything with an authoritative (correct) answer. I direct you to Calder's book, page 146 in this case, and you'll see one example. While he diagrams 240 volts, the connectors on p147 are rated at 250 volts. I suggest everyone look to a reference book to find the truth, and not get replies that are 82 percent incorrect.

 

[Maine Sail]

Don't know where JVISS lives, but he changes from 240 volts to 250 volts in mid-stream.

As usual on these forums, people shoot from the hip, "recalling from memory" what they think is correct, and as usual, no one recalls anything with an authoritative (correct) answer. I direct you to Calder's book, page 146 in this case, and you'll see one example. While he diagrams 240 volts, the connectors on p147 are rated at 250 volts. I suggest everyone look to a reference book to find the truth, and not get replies that are 82 percent incorrect.

It is threads like this, and the misunderstanding of electrical stuff, that keep me busy....

 

[kloudie1]

Carry on, Lad..
You are doing a fine job, Maine !

 

[Steve W]

It's funny, I got the answers I needed (yes I'm getting that Y whatever it is to use a 50A shorepower end into two 25A ship inlets. But this thread has taken on a life of it's own!

82% correct???? That sounds like someone actually sat down, compiled all the answers and divided all the "correct" ones to come up with that percentage

Anyway, Maine Sail, we're glad you're not bored.....

 

[tkanzler]

I direct you to Calder's book, page 146 in this case, and you'll see one example. While he diagrams 240 volts, the connectors on p147 are rated at 250 volts. I suggest everyone look to a reference book to find the truth, and not get replies that are 82 percent incorrect.

The nominal voltage, in the ranges used for small boat shore power wiring (and common single-phase wiring in buildings), is 120V and 240V nominal. Nominal as in 'name' - it is the official voltage designation in North America. The actual delivered voltage can drift around a bit, as there are tolerances on the 120/240V nominal as delivered from the utility, but that's how it's officially identified, and has been for a very long time.

110 and 220V is very old, and hasn't been the standard since well before I was born, though many folks, if not the majority, still use it in conversation. It's the nominal voltage in other countries, along with many others, but not around here.

Devices (receptacles, switches, etc.) are rated 125V and/or 250V. Look at any listed (UL, CSA, etc.) light switch, breaker (lighting and distribution, in land based applications), or receptacle, and you'll see 125V or 250V, or 125/250V. I don't know what the rating is for breakers intended for permanent installation on a boat, though.

In short:
125/250V - device rated voltage
120/240V - nominal voltage in North America, and usual non-motor utilization equipment voltage rating (like toasters and light bulbs)
115/230V - NEMA induction motor nameplate voltage rating (that would take another page to go into, but it's that way for a reason)
110/220V - obsolete in North America, but used by most folks in conversation. Also a common voltage in other countries, as is 50Hz power, though they're not necessarily related.

In the words of Michael Keaton, "220, 221; whatever it takes."

Edit: I haven't seen the page of Calder's book mentioned, but from the description given, Calder is correct in his useage of 240V in identifying the circuit, with devices (connectors) being 250V rated.

 

[jviss]

Don't know where JVISS lives, but he changes from 240 volts to 250 volts in mid-stream.

No I don't, I was using centerline's terminology in replying to him. I stated previously that the connectors are rated at 125 and 250 Volts, and that's what they are referred to in the standards and the parts books.

 

[Ron20324]

82% correct???? That sounds like someone actually sat down, compiled all the answers and divided all the "correct" ones to come up with that percentage

A while back someone PM'd me, thanking me for "cutting through the crap" as he put it. Seems he asked a wire/ampacity question, got 6 different replies, mine being to Goggle the charts to get it correct. So to assume ONE of the SIX was correct, that left 83.33334 percent wrong. My 2 cents:cussing:

 

[jviss]

The nominal voltage, in the ranges used for small boat shore power wiring (and common single-phase wiring in buildings), is 120V and 240V nominal. Nominal as in 'name' - it is the official voltage designation in North America. The actual delivered voltage can drift around a bit, as there are tolerances on the 120/240V nominal as delivered from the utility, but that's how it's officially identified, and has been for a very long time.

110 and 220V is very old, and hasn't been the standard since well before I was born, though many folks, if not the majority, still use it in conversation. It's the nominal voltage in other countries, along with many others, but not around here.

Devices (receptacles, switches, etc.) are rated 125V and/or 250V. Look at any listed (UL, CSA, etc.) light switch, breaker (lighting and distribution, in land based applications), or receptacle, and you'll see 125V or 250V, or 125/250V. I don't know what the rating is for breakers intended for permanent installation on a boat, though.

In short:
125/250V - device rated voltage
120/240V - nominal voltage in North America, and usual non-motor utilization equipment voltage rating (like toasters and light bulbs)
115/230V - NEMA induction motor nameplate voltage rating (that would take another page to go into, but it's that way for a reason)
110/220V - obsolete in North America, but used by most folks in conversation. Also a common voltage in other countries, as is 50Hz power, though they're not necessarily related.

In the words of Michael Keaton, "220, 221; whatever it takes."

Edit: I haven't seen the page of Calder's book mentioned, but from the description given, Calder is correct in his useage of 240V in identifying the circuit, with devices (connectors) being 250V rated.

It's interesting that the 110V distribution came from Edison's determination that 100V was optimal for lighting, both as a long life filament voltage, and in terms of safety, believing that a 100V shock was much less likely to be lethal than higher voltages. This was DC, too. Many characteristics of the system were retained when the switch to AC took place, which took a long, long time. Some places didn't complete the switch for some legacy apps until the 1970's and '80's (like parts of Columbia Presbyterian Hospital in NY). I think the change to 120 was in the '50's. The utility voltage is selected assuming some drop in distribution on the customer premises.

Something i don't get is why the device voltages are called ratings when in fact utility voltage tolerances are such that one could see more than the 125/250V ratings. Perhaps it's just legacy terminology?

 

[tkanzler]

The utility voltage is selected assuming some drop in distribution on the customer premises.

Which is also why motor rated voltage is 115V, 230V, 460V (480V nominal), etc. Induction motor performance and heating characteristics are very dependent on voltage, and even small voltage reduction have a large effect on the torque curve and current draw (exponential, in the case of the torque curve).

Something i don't get is why the device voltages are called ratings when in fact utility voltage tolerances are such that one could see more than the 125/250V ratings. Perhaps it's just legacy terminology?

I believe the industry tolerance is +5%, -10% at the service point, but I'd have to find the standard to be sure.

 

[Steve Dion]

Steve:

Here is the unit that will take that 50 curcuit and split it into two 30 amps...... but the prices!

http://www.jamestowndistributors.co...+Reverse+Y+Adapter+50A+125/250V+to+2-30A+125V

 

[mitiempo]

That one linked to is the reverse of what is needed. This is the one that the op needs and it is less expensive. http://www.jamestowndistributors.co...ame=Marinco+Y+Adapter+2-30A+to+50A+(125/250V)