Balance your loads and draw less amps

[SteveK]

I would refer you to my previous post. Loads do not have to be perfectly matched to benefeit.

Bud, I do not think I was disagreeing with you. Just pointing out the obvious. Boats do not have enough load items that run at the same time to create balanced loads that fulfill the theory. Even a 100 amp residence can be theoretically balanced but not operate balanced at all times.
220 heaters self balance, 2 110 heaters have to be both on to balance.
Not sure what you are arguing.

 

[Bud]

Bud, I do not think I was disagreeing with you. Just pointing out the obvious. Boats do not have enough load items that run at the same time to create balanced loads that fulfill the theory. Even a 100 amp residence can be theoretically balanced but not operate balanced at all times.
220 heaters self balance, 2 110 heaters have to be both on to balance.
Not sure what you are arguing.

Not arguing. Probably have different needs. This time of year we have air conditioners on 24 /7 down here in the Florida Keys. They work pretty hard, I would say compressors on 60 to 70% of the time. I have 4 air conditioners on my boat. Only run 2 most of the time unless we have a full boat or we are cooking (electric stove).

 

[Bud]

In the attempt to clear up the point I was initially making with this thread. Our limits for our electrical sources are in amps. All the breakers, the main breakers on our panels and on the docks. They are not labeled in watts. The size of the breaker in amps matches the size of the wire to prevent fire. The main breakers do not care if it is 125v or 250v they will trip if the amps exceed the rating no matter the voltage. That being said, on vessels like mine that have a lot of loads. (4-A/C's, frig/freezer, bait freezer, ice machine, washer and dryer, electric stove/oven, toaster oven, coffee maker, trash compactor, battery charger, soon to have watermaker, all 125volt. Balanced loads for things that will be on at the same time are not an option it is mandatory. I can't tell my family we can't run all 4 a/c's at night because there all on one leg and it would draw 60 amps, so I split them up between the two legs and we only draw 30 amps. We still have 20 amps left of our 50 amp service.
I am baffled by how many people want to dispute that in some way or bring the discussion back to power/watts. Our limitations are in amps.

 

[SteveK]

Bud, I think you are the confused one. so let me copy/paste what is readily available on the net.
Calculations
Volts x Amps = Watts is a basic electrical formula
Volts (V or E) x amps (A or I) = watts (P or power)

-Let's calculate watts for 120 volt single breaker
-15 amp single breaker. 120 volts x 15 amps = 1800 watts of power
-30 amp single breaker. 120 volts x 30 amps = 3600 watts of power.

-Calculate watts for 240 volt double breaker.
-15 amp double breaker. 240 volts x 15 amps = 3600 watts of power
-30 amp double breaker. 240 volts x 30 amps = 7200 watts of power.

With 240 volt, the watts or power is doubled .... Amps are not cut in half

IF you have shore/generator 50amp single feed (one line) it willnot matter what your electrical panel splits. But if you have 50amp twin feed then you have 50amps in both lines.
Your AC will use the same amount of power no matter how many lines, how many amp circuit you have. They will NOT use 1/2 total if split, but the total will be split between 2 feeds.

 

[Bud]

In the attempt to clear up the point I was initially making with this thread. Our limits for our electrical sources are in amps. All the breakers, the main breakers on our panels and on the docks. They are not labeled in watts. The size of the breaker in amps matches the size of the wire to prevent fire. The main breakers do not care if it is 125v or 250v they will trip if the amps exceed the rating no matter the voltage. That being said, on vessels like mine that have a lot of loads. (4-A/C's, frig/freezer, bait freezer, ice machine, washer and dryer, electric stove/oven, toaster oven, coffee maker, trash compactor, battery charger, soon to have watermaker, all 125volt. Balanced loads for things that will be on at the same time are not an option it is mandatory. I can't tell my family we can't run all 4 a/c's at night because there all on one leg and it would draw 60 amps, so I split them up between the two legs and we only draw 30 amps. We still have 20 amps left of our 50 amp service.
I am baffled by how many people want to dispute that in some way or bring the discussion back to power/watts. Our limitations are in amps.

This is some of the feedback I have gotten:
Don't expect to save on your electric bill.
The manufacturer should do that.
It doesn't matter because the loads are not always on at the same time.
You still draw the the same power/watts.
And my favorite- Thats silly, you don't draw any less volts, amps, or watts.

 

[sdowney717]

I am a little puzzled about the interest in balancing two legs of a 240V circuit. Yes, moving a load from the heavier used leg to the lightly used leg will result in less current in one and more in the other, but what good is that?

Presumably the wiring is sized to handle maximum loads, right? You won't save any voltage drop (and concomitant heat and wattage loss) because the voltage drop on one leg will be offset by an increased voltage drop on the other. So what is the big deal?

240V legs are unbalanced all of the time along the dock, depending on who is using single phase 120V and on which leg, but over lots of boat pedestals they generally all balance out.

I suppose there might be some advantage to balancing the legs from an on board genset, but not sure. Maybe balanced legs will smooth out the rotational torque required from the engine. Anyone know and does it matter?

David

IT really does not matter until your drawing closer or over the amp rating of the wire. 30 amp breaker wont trip at 31 amps, at least it takes quite a while to trip off. I did a test on my twin 30 amp breakers and they refused to trip off until I hit 37 amps. They would have eventually tripped off at less amps over 30 amps but it could take a while for them to get hot enough.

If it is power coming from your gen, then by all means balance the load on the legs. Will help it live longer. More amps produced means more heat on the windings and wear and tear. Why do generator windings burn out even when appropriately breaker protected, becuase of age and use, use it more heavily and it ages faster.

 

[Bud]

Bud, I think you are the confused one. so let me copy/paste what is readily available on the net.
Calculations
Volts x Amps = Watts is a basic electrical formula
Volts (V or E) x amps (A or I) = watts (P or power)

-Let's calculate watts for 120 volt single breaker
-15 amp single breaker. 120 volts x 15 amps = 1800 watts of power
-30 amp single breaker. 120 volts x 30 amps = 3600 watts of power.

-Calculate watts for 240 volt double breaker.
-15 amp double breaker. 240 volts x 15 amps = 3600 watts of power
-30 amp double breaker. 240 volts x 30 amps = 7200 watts of power.

With 240 volt, the watts or power is doubled .... Amps are not cut in half

IF you have shore/generator 50amp single feed (one line) it willnot matter what your electrical panel splits. But if you have 50amp twin feed then you have 50amps in both lines.
Your AC will use the same amount of power no matter how many lines, how many amp circuit you have. They will NOT use 1/2 total if split, but the total will be split between 2 feeds.

First of all if you had a single (phase) feed it would be 125v not 250v so it would not matter if your source from the dock was 125v. You would only have one leg and nuetral.
This is only applicable using 250v two phase, L1 and L2 and nuetral. The power formula you copied has no relevance to this discusion our limitation is in amps. The main breaker(s) on your panel or on the dock are in amps. what you draw through that breaker(s) can be optimized if balanced between both poles.

 

[SteveK]

 

[psneeld]

In the attempt to clear up the point I was initially making with this thread. Our limits for our electrical sources are in amps. All the breakers, the main breakers on our panels and on the docks. They are not labeled in watts. The size of the breaker in amps matches the size of the wire to prevent fire. The main breakers do not care if it is 125v or 250v they will trip if the amps exceed the rating no matter the voltage. That being said, on vessels like mine that have a lot of loads. (4-A/C's, frig/freezer, bait freezer, ice machine, washer and dryer, electric stove/oven, toaster oven, coffee maker, trash compactor, battery charger, soon to have watermaker, all 125volt. Balanced loads for things that will be on at the same time are not an option it is mandatory. I can't tell my family we can't run all 4 a/c's at night because there all on one leg and it would draw 60 amps, so I split them up between the two legs and we only draw 30 amps. We still have 20 amps left of our 50 amp service.
I am baffled by how many people want to dispute that in some way or bring the discussion back to power/watts. Our limitations are in amps.

Are you saying you are drawing 30A total or 30A per leg with 4 ACs running?

 

[Bud]

Are you saying you are drawing 30A total or 30A per leg with 4 ACs running?

30 amps total on each 125v leg

 

[boathealer]

Bud, I think you are the confused one. so let me copy/paste what is readily available on the net.
Calculations
Volts x Amps = Watts is a basic electrical formula
Volts (V or E) x amps (A or I) = watts (P )

.... [snip] The power formula you copied has no relevance to this discusion our limitation is in amps......

Really? Are you serious?

 

[Bud]

It is a simple concept. If you use both sides of your source power(L1 and L2) you can get more out of it and your nuetral current goes to zero(except for the unbalanced portion).
Whats not to love about that.

How about an analogy. A boat with twin engines 210hp each. Why would you run one engine at say max 3200rpm's to get 8 knots or run both engines at 1600rpm's and get 8 knots. Arguing that it is the same horse power running one engine at 3200 versus two at 1600 is the same argument that the your using when you say your using the same amount of watts or power no matter which leg you run your current through.

Disclaimer: Assumes that the relationship between engine rpm's and speed are linear also assuming relationship between rpm's and horsepower are linear.

 

[Bud]

Running 25amps through two legs of your source power is less wear and tear than running 50 amps through one side, connections heat and so forth. Then nuetral current going to zero on a perfect balance is bonus, even thuogh electric company does not meter the nuetral. Thats like using less fuel or having better longevity running the two engines at 1600rpm's versus one at 3200rpm.

 

[psneeld]

That's where you are not connecting with me and may be others



You are using exactly the same amount of fuel.


You even said it in your last post answering my question.



I understand on a 2 leg system you get only max power only if the loads on one leg don't exceed the breaker for that side. But guess what, that's true of 2 - 30 amp cords too.


While I agree running at max amps 24x7 may not be good if at capacity (and I am not sure everyone would be)....I am not sure there is much in the wear and tear department on simple electrical systems compared to mechanically moving parts.

 

[Bud]

That's where you are not connecting with me and may be others



You are using exactly the same amount of fuel.


You even said it in your last post answering my question.



I understand on a 2 leg system you get only max power only if the loads on one leg don't exceed the breaker for that side. But guess what, that's true of 2 - 30 amp cords too.

While I agree running at max amps 24x7 may not be good if at capacity (and I am not sure everyone would be)....I am not sure there is much in the wear and tear department on simple electrical systems compared to mechanically moving parts.

How about the fact that the nuetral current is eliminated on a balanced load between L1 and L2. Is that not being more effecient

 

[Bud]

 

[Bud]

Made it bigger.

Is it better to draw 20 amps through the two legs (2 wires) or put them both on leg 1 and draw 40 amps through one leg and nuetral (2 wires).

 

[SteveK]

View attachment 94017

Made it bigger.

Is it better to draw 20 amps through the two legs (2 wires) or put them both on leg 1 and draw 40 amps through one leg and nuetral (2 wires).

20 amps in L1 + 20 amps in L2 = 40 amps
Until you exceed 80% of the rated cord and plug it does not matter. A 50 amp 125V outlet will supply a safe continuous 40 amps.

 

[Bud]

20 amps in L1 + 20 amps in L2 = 40 amps
Until you exceed 80% of the rated cord and plug it does not matter. A 50 amp 125V outlet will supply a safe continuous 40 amps.

Your making my point, would you rather draw 20 amps through two wires or 40 amps through two wires. Not to mention if your breaker is 30 amp.

 

[Bud]

20 amps in L1 + 20 amps in L2 = 40 amps
Until you exceed 80% of the rated cord and plug it does not matter. A 50 amp 125V outlet will supply a safe continuous 40 amps.

You hope. No where in that circuit of L1 and L2 if you put a clamp on ammeter will it say your drawing 40 amps. The reading you will get is 20 amps. They are not additive in this application. Even if you wanted to calculate the watts you wouldn't add the amps it would be the product of 240v x 20amps. The breaker will see either 40 amps through one poll or 20 amps through both poles. your choice

 

[psneeld]

Uh... Am pretty sure you would clamp read 20A on L1 and 20A on 2.


My panel has an amp meter on both legs.....

 

[Bud]

Uh... Am pretty sure you would clamp read 20A on L1 and 20A on 2.


My panel has an amp meter on both legs.....

Allright so then how do you figure what you can draw total for your panel. Do you add the amps on one side to the amps on the other side, No you do not

 

[SteveK]

View attachment 94016

The heat pump draws 20 amp and the combined house circuits draw 20 amps but of course 20 amps total measured anywhere along L1 or L2 is 20 amps. Somehow 20 amps or 1/2 of the draw disappears or does it?
Actually if the neutral reads zero in a balanced system, each leg will read the same amount AND if you then clamp both L1 & L2 at the same time it will read zero.
So Bud should complain to the marina if he gets a hydro bill after balancing the load.

Simplified, Marinas routinely clamp onto the cable and expect to read zero, otherwise there is a leak, perhaps to ground or worse to water.

 

[psneeld]

Allright so then how do you figure what you can draw total for your panel. Do you add the amps on one side to the amps on the other side, No you do not

Each leg is 50A (ok a little less the experts tell me)....so I keep the total on each leg to around 40A or less ....If I was drawing more than 40A consistently, and way less on the other leg than I would balance...but the total number of amps on L1/L2:would remain the same.


Plus, my oint was that you CAN measure the individual legs unless I have been misled for 50 years.

 

[Bud]

Each leg is 50A (ok a little less the experts tell me)....so I keep the total on each leg to around 40A or less ....If I was drawing more than 40A consistently, and way less on the other leg than I would balance...but the total number of amps on L1/L2:would remain the same.


Plus, my oint was that you CAN measure the individual legs unless I have been misled for 50 years.

Yes you can measure the individual legs but the amps are not additive when the two loads are in series as displayed in the schematic I posted

 

[Bud]

Yes you can measure the individual legs but the amps are not additive when the two loads are in series as displayed in the schematic I posted

The total amount of amps would be reduced by putting more of the loads in series.

 

[Bud]

Each leg is 50A (ok a little less the experts tell me)....so I keep the total on each leg to around 40A or less ....If I was drawing more than 40A consistently, and way less on the other leg than I would balance...but the total number of amps on L1/L2:would remain the same.


Plus, my oint was that you CAN measure the individual legs unless I have been misled for 50 years.

The total amount of amps would be reduced if you put more loads in series.

 

[Bud]

Each leg is 50A (ok a little less the experts tell me)....so I keep the total on each leg to around 40A or less ....If I was drawing more than 40A consistently, and way less on the other leg than I would balance...but the total number of amps on L1/L2:would remain the same.


Plus, my oint was that you CAN measure the individual legs unless I have been misled for 50 years.

Using your example if you were to move 10 amps of your 40 amp load over to the other leg that draws "way less" you would reduce your amp draw to 30 amps total. Then the difference of the loads on the two legs is what the nuetral would be drawing.

 

[psneeld]

I guess the usual electrical wizards have given up on this thread for a reason?

 

[psneeld]

30 amps total on each 125v leg

From post #40......