220v Question

[Chasemmc]

Replacing all in one stacked washer & dryer with separates. New install requires a separate 120v outlet. Wired 120v off one leg of the 220v thru an additional 20amp breaker. When testing with multimeter, one leg of 220 is 120v, one leg is 114v. Is this okay or is it an indication that something is worn out and needs to fixed

 

[Boatsb]

The 120v should be seperate from the 240v. You cant just pull a single leg off the 240 line to the washer. For 20 amps. That's not the right way to do it.


When in doubt hire it out. Get a good marine electrician if your not sure how it should be done. Boat fires suck.

 

[Pascal]

I assume you pulled the 120 from the panel and not from the existing 240 outlet

Some slight voltage variations between either hots of a 240 v and neutral happen, that s ok

 

[Captain Ralph]

Quick North American, single phase, 240-120 Volt Alternating Current Theory;
240volts A C, is the full swing of typical electric service to docks and homes. A picture of its graft (plot) of the A C wave cycles from 120v positive to 120v negative, above-below a zero point called neutral. We can use this full swing of 240v by attaching wires to just the top and bottom of this full swing. We can also find one of the two 120v sources by attaching wires to either the top or bottom and the zero or neutral point.
These wires are normally colored Black, Red and White. 240v panels on boats usually have rows of breakers for 240v options and dual rows of 120v options. These 120v rows are half of the 240v service using the common neutral as a zero or dividing point.

The O P is correct in his installation of a single 120v breaker for his new option.

Observing different 120v levels should not happen after an isolation transformer found on most Hatts.
A heavy 120v load on the low side could explain it.
Without a transformer, on a dock, a few volts difference can be possible with out any concern. You can always light up your gen set and ensure if on-board of a dock issue. Also start turning off the low sides breakers to ensure you can identify an onboard load (ie block heater).

 

[Boatsb]

There should be no voltage variation (more than a volt or 2) in the 2 legs. It's not possible on a properly set up system

 

[jim rosenthal]

Please let me know if I am wrong, but isn't it true that when you measure voltage of any kind, you are actually measuring it with respect to something- either to ground, or to a lesser or greater voltage? In other words, you are measuring a difference in voltage. Isn't that correct?So when you measure one leg of a 240vac receptacle for example, you are measuring the difference in voltage between the top of the wave and the neutral or midpoint?

 

[davidwigler]

Does your 240 volt line have four wires or three? You need four to get 120v without improperly using the ground as a neutral.

 

[Boatsb]

Voltage is potential. Amperage is actual work

Voltage may drop with higher amp draw. That would be a sign of imbalance in the 120/240 system

 

[Captain Ralph]

Please let me know if I am wrong, but isn't it true that when you measure voltage of any kind, you are actually measuring it with respect to something- either to ground, or to a lesser or greater voltage? In other words, you are measuring a difference in voltage. Isn't that correct?So when you measure one leg of a 240vac receptacle for example, you are measuring the difference in voltage between the top of the wave and the neutral or midpoint?

If I understand your question correctly,, Yes & No.. when you measure 120Vac, you are measuring the wave to to neutral or zero line.
240Vac is measure total swing (peak to peak) and neutral or zero line is not involved.

Does your 240 volt line have four wires or three? You need four to get 120v without improperly using the ground as a neutral.

None of my comments have involved ground, fault return or green wire,, yet..

I hope the O P went to a new breaker on the panel for his 120Vac. In re-reading the O P post #1, I am now concerned.
If the O P pulled 120Vac off of the clothes dryer outlet, this would be improper and a concern for a few reasons. There is no Neutral lead in the old Crows Foot 3 wire out let. Using the green lead for neutral is against every electrical code there is before ABYC was ever created. This is an example of why the new dockside GFI breakers are popping.
If it was a 4 wire lead with the white and green wire separate, and the white (neutral) and red or black lead used for 120Vac, it would work,, PENDING; This modification was built as a sub panel with a new dryer breaker next to the washer breaker, The breaker at the main panel upgraded to supply the new total current requirements and the wires between the main panel to the new sub panel are of large enough in size to carry to spec, the additional current required. If none of these are so, it is not safe and not to any code.

 

[Boatsb]

Look at the victron site for auto transformers. The 100 amp is well below a boat buck and the data sheet may explain what it does and why you should see equal voltages on both legs.

If the boat does not have a clean 240 input balanced to both legs it's not efficient.

That unit does not boost 208 to 240 though

 

[Captain Ralph]

Look at the victron site for auto transformers. The 100 amp is well below a boat buck and the data sheet may explain what it does and why you should see equal voltages on both legs.

If the boat does not have a clean 240 input balanced to both legs it's not efficient.

That unit does not boost 208 to 240 though

I have installed these auto-transformers. Ideal for balancing 120V loads on a 240v supply.
Great for gen-set outputs when you really want the winding loaded equally.

I would not use this to cover up an imbalance with out knowing what the imbalance is first.
There could be a bad connect or a load left on.

 

[Boatsb]

If you have 2 lines at different voltages it's a problem.

Balancing the load between 2 legs is not fixing a connection problem. It's a system level solution to variable loading and efficiency.

When designing a system it allows the 2 legs to both work up to their full potential without overloading the neutral. On a 30 amp system you dont have alot of headroom so 2 AC units could fry a cord to the pedestal. If you load balance through the transformer and have large enough wire in the system you can safely run 30 amps to the air conditioners without frying the pedestal and power cord.

With the 100 amp unit a 50 amp boat will easily balance the 2 legs safely BUT you have to have the correct size breakers for the wire size not the transformer. It's not a DIY kind of thing without some design and install support.

 

[Chasemmc]

Its a 4 wire cable with both a neutral and ground. Two 30amp breakers in the panel.

 

[Boatsb]

I think it's a 50 amp breaker. At least I hope so. My 41c runs at the limits of 2 x 30 amp lines.

 

[Captain Ralph]

Its a 4 wire cable with both a neutral and ground. Two 30amp breakers in the panel.

Your answer is thin but it does not look good. Give us a schematic or I will assume a picture you just branched off a 120Vac lead to your dryer leads witch is not correct.
Please re-read post #9. How does your work compare?

 

[Captain Ralph]

If you have 2 lines at different voltages it's a problem.

Balancing the load between 2 legs is not fixing a connection problem. It's a system level solution to variable loading and efficiency.

When designing a system it allows the 2 legs to both work up to their full potential without overloading the neutral. On a 30 amp system you dont have alot of headroom so 2 AC units could fry a cord to the pedestal. If you load balance through the transformer and have large enough wire in the system you can safely run 30 amps to the air conditioners without frying the pedestal and power cord.

With the 100 amp unit a 50 amp boat will easily balance the 2 legs safely BUT you have to have the correct size breakers for the wire size not the transformer. It's not a DIY kind of thing without some design and install support.

I think it's a 50 amp breaker. At least I hope so. My 41c runs at the limits of 2 x 30 amp lines.

I am confused why you are distracting from a post and configuration issue and inserting a issue and fix that is not a problem here?

 

[Boatsb]

Mark.


The input from the pedestal on your boat should be a 50 amp 125/250. Many larger vessels have 2 of these by the way

The line to the washer dryer (220 volt) should be substantially less amperage. Probably less than 20 amps.

A 15 or 20 amp 120 volt outlet may be also needed for the washer.

As your use of 120 volt systems changes the balance changes. That's where the transformer makes things more efficient and safer.


Call me tomorrow if you need to get deeper into this. It's not a big problem to fix but I'm seeing a bit of confusion on the forum.

 

[Chasemmc]

I'll be up there tomorrow & I'll take pix of panel. i think its a 100amp service and the 220 runs through 2-30amp breakers. It also has 2 isolation transformers. What I'm hearing right now is Scott says run another home run to the breaker box. Others are saying maybe. I'll put multimeter on the 220 and turn off the other breakers to see if the voltage changes. I can also fire up the generator to see if that changes anything.

 

[Chasemmc]

I'll be up there tomorrow & I'll take pix of panel. i think its a 100amp service and the 220 runs through 2-30amp breakers. It also has 2 isolation transformers. What I'm hearing right now is Scott says run another home run to the breaker box. Others are saying maybe. I'll put multimeter on the 220 and turn off the other breakers to see if the voltage changes. I can also fire up the generator to see if that changes anything.

 

[Pascal]

I doubt you have 100 amp sore power on a 56 .... the plug for 100 is big with 4 large round pins, not thin blades like the 30 or 50