I want to run my 240v us mini splits by themselves off grid,alone, what inverter did you use?
240 split phase vs 230v European inverter and US split phase devices
- Thread starter Watts Happening
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I haven't installed yet but I bought mpp lv6048 for this
RCinFLA
Solar Wizard
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Just double check, there are a few 240vac split-phase mini-splits that also use 120 vac to run their electronics power supply and relays like reversing valve. If it has a neutral wire connection it is a sign it also requires 120vac.
Quattrohead
Solar Wizard
Are there ? Any examples because I think they are all made for worldwide use and no one else is daft enough to use split phase.
The mini splits I use are Mr cool and home Depot types and there wiring is l1 ,l2, G no neutral connection, I just don't know if l1 and l2 need to be 180 degrees opposite phase wave or if that even matters on minisplits
timselectric
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It's single phase.
So, only one waveform.
MartyByrde
Off-Grid Innovator
I’m working on an off grid setup for electrical equipment that runs solely on 240v. From what I’ve garnered I would have the L and N from the EU 230vac inverter into a 240v circuit breaker and bond N and G at the main panel?
Yes, unless the N and G are bonded in the inverter. At any rate, you're going to have an odd ball system. You will have to use breakers with a "straight rating" of 240 volts. Your average run of the mill breaker has a rating of 120/240, which means that it is intended for use on a system with a maximum of 120 volts to ground. Your system will have a voltage of 240 to ground and therefore a standard breaker won't work.
zanydroid
Solar Wizard
I wonder if it’s better to do straight 240 or just use Euro-style breakers and consumer units.
Assuming using standard North America breakers… are you supposed to use single pole breakers?
Assuming using standard North America breakers… are you supposed to use single pole breakers?
Hedges
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On a breaker panel busbar, it would have to be single pole.
Many Square D QO breakers are only 120V per pole. The 2-pole 120/240V breakers are 120V per pole. The 3-pole breakers are all 277V, I think and some model number single pole and 2-pole breakers are.
DIN rail, many are. Like the Midnight CBI and Carling breakers. Some may have a Midnight sticker or web site listing that giving lower voltage, but the manufacturer sticker with part number and voltage is underneath.
Many Square D QO breakers are only 120V per pole. The 2-pole 120/240V breakers are 120V per pole. The 3-pole breakers are all 277V, I think and some model number single pole and 2-pole breakers are.
DIN rail, many are. Like the Midnight CBI and Carling breakers. Some may have a Midnight sticker or web site listing that giving lower voltage, but the manufacturer sticker with part number and voltage is underneath.
There is no reason you couldn't use a double pole breaker and open the neutral with the hot. It just has to be a straight 240 volt breaker.
Hedges
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If a double-pole breaker, it needs to be one where each pole individually is rated to 240V.
If you have 240V Line and 0V Neutral, two ganged 120V poles in series (one in Line, one in Neutral) will trip for an overload just fine.
However, if Line shorts to Ground (which is bonded to Neutral somewhere, only the pole on 240V line is available to break the arc. Because it is only rated for 120V (per pole), expect it to burn and fail to interrupt the arc.
If you are able to wire both 120V poles in series to interrupt Line, rather than having one open Neutral, then it would work.
Right, that's what's called a straight rated breaker, a breaker with a 240 volt only rating. They exist, you just have to find them.
MartyByrde
Off-Grid Innovator
So this wouldn’t work https://www.homedepot.com/p/Leviton...Volt-Thermal-Magnetic-R00-LB220-0TR/312392693
Would it be easier to find breakers in the US by running the inverter in 3 phase assuming three or more inverters?
Hedges
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QO has them for 3-phase panels, which often carry 277V (Hmm, finding 240V not 277/480V). Same form factor as the split-phase panels. Schneider's website details ratings of the different models.
240V:
240V:
www.se.com
I think these were the Midnight breakers that said 120/240V but were actually CBI breakers rated 277V
These I think are from Carling and are sold by Midnight as 277V, but are only "supplementary protectors", which may mean they don't provide a full 1" of isolation between input and output, possibly other differences.
diysolarforum.com
240V:
240V:
QOXD120 - Mini circuit breaker, QO, 20A, 1 pole, 240/415VAC, 3kA, plug in mount | Schneider Electric USA
Schneider Electric USA. QOXD120 - Mini circuit breaker, QO, 20A, 1 pole, 240/415VAC, 3kA, plug in mount.
www.se.com
I think these were the Midnight breakers that said 120/240V but were actually CBI breakers rated 277V
These I think are from Carling and are sold by Midnight as 277V, but are only "supplementary protectors", which may mean they don't provide a full 1" of isolation between input and output, possibly other differences.
Testing Magnetic-Hydraulic circuit breakers
I've built myself a circuit breaker tester. I assembled three transformers into a 3-phase wye auto-transformer, and by means of a breaker and cord/plug it can be repurposed into a current multiplier. A breaker connects X1 to H2 and H3, providing 4.7x current boost on X2 paralleled with X3...
diysolarforum.com
MartyByrde
Off-Grid Innovator
Thanks for the information. Looks like Midnight Solar has great options.QO has them for 3-phase panels, which often carry 277V (Hmm, finding 240V not 277/480V). Same form factor as the split-phase panels. Schneider's website details ratings of the different models.
240V:
240V:
QOXD120 - Mini circuit breaker, QO, 20A, 1 pole, 240/415VAC, 3kA, plug in mount | Schneider Electric USA
Schneider Electric USA. QOXD120 - Mini circuit breaker, QO, 20A, 1 pole, 240/415VAC, 3kA, plug in mount.
I think these were the Midnight breakers that said 120/240V but were actually CBI breakers rated 277V
These I think are from Carling and are sold by Midnight as 277V, but are only "supplementary protectors", which may mean they don't provide a full 1" of isolation between input and output, possibly other differences.
Testing Magnetic-Hydraulic circuit breakers
I've built myself a circuit breaker tester. I assembled three transformers into a 3-phase wye auto-transformer, and by means of a breaker and cord/plug it can be repurposed into a current multiplier. A breaker connects X1 to H2 and H3, providing 4.7x current boost on X2 paralleled with X3...
This would also be a straight 240v breaker?
100A, 240V AC, 60V DC, 1 Pole, DIN Rail Mount Miniature Circuit Breaker, Trip Curve: C, UL1077 https://a.co/d/aPSy950
Trying to also conceptually understand why someone would use a DIN rail vs main panel box?
Do DIN rails have current ratings like a main panel box?
Are there applications where one would prefer one over the other?
Last edited:
Hedges
I See Electromagnetic Fields!
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Yes.
Note that it is a UL 1077 "Supplementary Protector", not a UL 489 "Breaker", therefore not an isolating device that should be used for safety between utility grid and humans working on wiring.
Not that you would normally notice any difference. Only if there was a transient on the grid maybe?
Curve C. Note there are different curves, overload amount and time before trip.
DIN rails are normally not current-carrying components, so wouldn't have ratings. Except I see them grounded by green wire connectors; maybe that is only to ground the box, not as a ground conductor.
There are a bunch of parts available DIN rail including relays, power supplies, fuse holders, etc. so it allows modular design of various functions.
If you want a busbar, that is an extra part mounted on the breakers, e.g. for a combiner.
I would choose based on what parts/functions I wanted. I'm using QO breaker panels exclusively, except I have DIN rail to hold load-shed relays and then put in Midnight magnetic-hydraulic breakers after finding paralleled QO breakers didn't share current evenly. Also, I can cut and mount a DIN rail where it fits, like inside a disconnect switch.
If I wanted an offgrid 240v breaker panel ONLY (in U.S.) for my two mini splits and well pump which are all two ungrounded conductors and a ground wire. In this example, the panel will be fed from a Victron EU 230/240v inverter and never connected to grid AC IN. 1) would this work and 2) where would the grounding take place?
1) It would work
2) The N output would be grounded
This leads to the same problem discussed above: Technically, the breakers used would need to be straight rated for 240 volts instead of slash rated 120/240. I suppose a way around this would be to use fuses instead of breakers.
The reason why straight rated breakers are required by code is due to the available fault current from the grid during an asymmetrical fault, that is, a fault from line to ground. I suppose that an off grid inverter would never be able to provide those kinds of fault currents so a standard slash rated breaker will probably be fine. But the code doesn't make an exception for the power source.
If it were me, I'd probably just use regular breakers, but I'm not offering that as advice because it is a technical code violation.
If it were me, I'd probably just use regular breakers, but I'm not offering that as advice because it is a technical code violation.
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