Wire Gauge From MPPT 5kw 48VDC 60A Charge Controller to new breaker panel? 9 total 20A circuit breakers + 60 incoming Main Breaker.

[Sun_Dried_Toad]

Due to a small mistake on my suppler's end, I was unable to install my solar array this weekend as planned. instead, I'm wiring in everything else.

I live in a stick built, house on foundation. We have (soon to be "had") standard grid power. We have 240V available coming in from the grid, via two individual 120 cables from the meter, attached to two sides (lugs) of our power distribution (breaker) panel.

We have central HVAC which runs on 240V. We also have a clothing dryer which runs on 240V. THOSE ITEMS WILL NOT BE MOVED TO THE NEW, SOLAR SYSTEM. they will remain on the grid system. As such, we will only need 120V in our new breaker panel for all 9 of our circuits inside our home.

My new breaker panel will receive power (120VAC) from the "Bright" or "BR SOLAR" brand charge controller. Model: MPPT-5KW 48VDC 60A

EDIT: this system is powered by 8 QCELL panels, 305 watts each.

despite what the front of the charge controller says, it puts out 120v single phase AC. it does not put out 240v. this was verified by my supplier. prior to shipping my system out, he connected it all, and ran it, to ensure everything was working. I don't know if he had to modify it to 120 or what. all I know is that he told me it makes 120v. upon arrival, I saw the front of the controller stated 240v. I contacted him, and he assured me it makes 120v.

the lugs for the "AC out" terminals on my charge controller look like they will only accept 10AWG wire. This means my entire home's power supply must travel through 3 feet worth of 10AWG wire to get to my 60A breaker, and through it, into my power distribution (breaker) panel. is this acceptable? Looking at the cable that comes in from the pole, through my meter, and into my existing grid supplied breaker box (via a 60A main breaker) is probably #2 AWG wire/cable.

let me itemize my EXISTING GRID breaker panel for clarity:
there are TWO 120V hot cables coming in. each ties to one of two lugs. we will refer to these as North and South lug. of course, there is also one common.
the ONLY breakers that receive power from both North and South lugs are my HVAC and clothes dryer. THESE ARE NOT PART OF THE SOLAR BOX.
that said, we will discuss only the 120v breakers that will be in the new box.

I have 3 tandem breakers in the old, grid box. in the new box, these will be slimline style. same thing, different shape. two circuits on one breaker clip.
I will refer to the tandem/slimline breakers as A&B of its clip in panel number.

1A. Our wine room ceiling fan/light, Guest room east wall outlets
1B. kitchen refrigerator, dishwasher

2. obsolete/deleted/omitted - (clothing dryer) shares breaker clip in #4 for 240v

3A. clothing washing machine
3B. Laundry room light, dining room fan/light, 120v outlet behind love seat.

4. obsolete/deleted/omitted - (clothing dryer) shares breaker clip in #2 for 240v

5A. kitchen LED light, Microwave.
5B. Hallway lights, main bathroom vanity lights & overhead (ceiling) socket intended for heat bulbs (usually has CFL "regular" bulbs in it)

6. living room fan/light, west side garage outlets, garage door opener, garage fluorescent light ballast, garage refrigerator.

7. fish tank pump/filter in dining room, master bedroom fan/light, master bathroom vanity lights.

8. outlets on east wall of garage, oven/range vent hood, garage chest freezer SEE NOTES BELOW ON #8 OTHER ITEM

9. Obsolete/Deleted/Omitted - OLD ELECTRIC OVEN/RANGE. WE NOW HAVE A GAS OVEN RANGE. (shares slot #11 for 240V)

10. MAIN BREAKER for incoming power 60Amp. shares slot #12 to energize North and South lugs with 120v each.

Special notes about #8 breaker: something attached to this breaker causes the HVAC system to shut down when flipped to "off" position. IT IS DOES NOT SUPPLY POWER TO THE OUTDOOR CONDENSER/COMPRESSOR UNIT. It is a 120v circuit, the compressor/condensor unit is 240v. when the #8 breaker is tripped, or turned off, the 240v to the condenser/compressor is STILL LIVE. this stated, I think that the #8 breaker controls the indoor unit. The evaporator coil, gas furnace and blower unit that distributes HVAC air throughout our home, is mounted in our attic. I think that it has a safety kill switch that causes the contractor coil to drop out on the outdoor compressor/condenser unit to prevent evaporator freeze up and compressor burn out.

there are a few small circuits not listed, but they are just some mostly unused outlets and our guest bedroom fan/light. we just didn't get them listed in our map when we made it. they are on the above listed circuits, just not in the list.


My new panel has 4 less slots. it is an 8 breaker panel. #6 and #8 are reserved for the 60 amp main breaker, so it is actually a 6 breaker panel.

This could change, but here goes a basic/generic list of the new panel:

1a. wine room fan/lights, guest room east wall outlets
1b. kitchen fridge, dish washer

2. living room light/fan, west garage outlets, garage refrigerator, garage door opener, fluorescent ballast light

3a. clothes washing machine
3b. laundry room light, dining room light/fan, 120v outlet behind love seat

4. East wall garage outlets, garage chest freezer, Range hood, SEE NOTES ON #8 ABOVE

5a. kitchen LED light, microwave
5b. hallway lights, main bathroom vanity & overhead lights.

6 & 8. Main 60amp incoming power breaker. only 1 leg of 120v comes out of my charge controller. I plan to split that one leg into a "Y" and feed the split leg into both lugs of the double throw 60 amp breaker mounted in slots #6 & #8 to energize both lugs (North and South) of the entire new solar dedicated breaker box.


FINALLY, my questions:
1. is there any reason that I cannot depend upon my charge controller to supply my home with enough power?

2. Can I split my 120v coming out of my controller into a "Y" to feed both sides of my 60a main breaker?

3. if 2 is correct, will my 60a breaker work as it should?

4 is 10AWG wire/cable coming from my "AC out" lugs on charge controller to my 60a main breaker in new box acceptable, or is it too small?


FINAL BIT OF INFO FOR REFRENCE:

on an average day, if we turned everything that we normally use in our house on at the same time, we would use approx 2,800KW in an hour.

we never do this.

my wife and I live alone, and are child-free by choice.

at any given time, we have running:
chest freezer
garage refrigerator
kitchen refrigerator

and we may also have a few lights, our television, her fish tank pump, and a few ceiling fans.

most other things are seldom. we run dish washer when at work, so few other loads. clothes washer on Mondays, blender for few seconds in the morning, maybe her playstation once a week for an hour our two.

being just the two of us, we don't really use much electricity. I mean we do... but it's generally a light load.

 

[gnubie]

Bright's marketing strategy seems to be to make their products and documents look as much like Victron's as they can without getting sued out of existence.

If it really is limited to 10AWG at the terminals that's way undersized for a 60A unit. You could trim down your wire or fit a narrow nose crimp connector to the end of the wire so that it fits in the terminal as a last resort. How many watts of solar panels do you plan on connecting to it, that'll determine the maximum current that can come out on the battery / load side of the controller.

*edit*

That looks like an inverter / charger. If we are talking about the 120VAC output to your panel and if the 5kW figure holds true, that's about 40A max and within the abilities of 10 AWG to carry but I'd rather see heavier.

 

[Sun_Dried_Toad]

Bright's marketing strategy seems to be to make their products and documents look as much like Victron's as they can without getting sued out of existence.

If it really is limited to 10AWG at the terminals that's way undersized for a 60A unit. You could trim down your wire or fit a narrow nose crimp connector to the end of the wire so that it fits in the terminal as a last resort. How many watts of solar panels do you plan on connecting to it, that'll determine the maximum current that can come out on the battery / load side of the controller.

*edit*

That looks like an inverter / charger. If we are talking about the 120VAC output to your panel and if the 5kW figure holds true, that's about 40A max and within the abilities of 10 AWG to carry but I'd rather see heavier.

We have 8 QCELL panels @ 305 watts each.

 

[gnubie]

OK, so thats about 50A to the battery, 10 AWG would be at the limit there. I wouldn't like that sort of current flowing over it.

You also need to watch current from the battery back to the inverter. That's over 100A at 5kW. 10 AWG simply won't hack that. Can you take a picture of the terminals showing the wire entry and make some measurements? That'll let people see if it really is only capable of 10 AWG.

I'm hoping this isn't all a case of the unit having the CE mark, ie Chinese Exaggeration.

 

[Sun_Dried_Toad]

the cables to the battery bank are larger. As best as I can tell, the wires to the battery bank are around #3 or #4.

That said, I am not an expert on AWG.

I went to Home Depot to buy some extra cable, and told the guy I needed what I thought would be #2. he showed me what he called #3 (didn't think AWG came in odd numbers) and it looked the same as my largest cables, used for my batteries and battery to controller connections.

bought it, came home, compared it, and it looks virtually the same. if it is any smaller than my factory battery cables, you would need a caliper to confirm the difference. naked eye can't call it effectively.

 

[Sun_Dried_Toad]

t

OK, so thats about 50A to the battery, 10 AWG would be at the limit there. I wouldn't like that sort of current flowing over it.

You also need to watch current from the battery back to the inverter. That's over 100A at 5kW. 10 AWG simply won't hack that. Can you take a picture of the terminals showing the wire entry and make some measurements? That'll let people see if it really is only capable of 10 AWG.

I'm hoping this isn't all a case of the unit having the CE mark, ie Chinese Exaggeration.

on the left is the battery cable that came with the system. all battery related cable is identical size.

on the right is what I bought at Home Depot, which he called a #3.

 

[gnubie]

Without seeing the terminals its hard to tell but at least you have wire that can handle the DC side. 5kW at 120VAC is 42A so you are within the limits there for 10 AWG if the wire isn't in conduit etc which would cause it to get hotter due to no air circulation. Depending on the inverter a 60A breaker may never pop because the inverter may never be able to provide 60A on the AC output.

 

[Sun_Dried_Toad]

for what it's worth, the model plate claims "60A" on the Charge controller.

However, as you stated, that may just be a case of Chinese Embellishment.

Would you recommend that I drop down to a 50 amp breaker for functionality? would a 50 amp main allow me to run my home without popping constantly?

My home has run on a 60 amp breaker with no issues for all 20 years I have lived here.

additionally, I have now removed three high draw items from the equation as it pertains to this solar system. we no longer have an electric oven/range. we did not move the clothing dryer to the solar system. the HVAC compressor/condenser (outdoor unit) is not on solar system.

the controller also has a built in AC out breaker built in. I do not know what amperage it is rated. it does not say in English.

 

[gnubie]

The breaker size is a good question.

It really comes down to how the inverter behaves and I can't find any decent documents for that. If the inverter is the only way AC comes out of the unit, it can never do more than about 42-ish amps, but we don't know anything about any surge / overrate the unit can do. If it is about 42A max a 50A breaker wouldn't be able to pop. The 10 AWG is rated to 55A in your application so strictly speaking it can handle the full output of the inverter continuously. The catch is, does the unit have a bypass mode where AC into the unit can flow straight to the output. If it can, then potentially you have more than 60A available on the output. Does the unit have real surge / over rating available for a short time. If it can it may be able to supply more than 60A again.

I'd like to see 8 AWG really. That'd cover you for the continuous 42A out of the inverter and also let it cope with over 60A if the bypass mode exists so that 60A breaker can pop before there is a heating problem with the wire. The AC wire into the inverter and it's breaker needs to be considered too, if you plan on having AC going into the inverter.

Unfortunately without any real documentation to go on this is all a bit of a guessing game.