Community Forums

lentineaz · 02-03-2023, 08:50 PM

Evening Everyone,

I have a Multiplus 12/3000/120-50 120v.

My issue is this - I need to run from my shore power in the back of my RV to my Multiplus under my bed, which is approximately 35 feet. I then need to go from the Multiplus basically back to the same location as that is where my WEC AC/DC RV power station is.

My RV currently using 10/2 Orange Romex for these connections BUT it's only going about 5 feet in total.

From what I have read, at the below links, voltage drop off should be less than 3% at that distance which means it should work without any issues. I am just not super confident in this conclusion and would love to hear peoples opinion.

https://www.southwire.com/calculator-vdrop
https://learnmetrics.com/30-amp-wire...0amp%20service.
- states I should use 8/2 or 6/2 for thishttps://www.thespruce.com/wire-size-underground-circuit-cable-length-1152899
- states I can run 64 feet without any issues using 10/2
https://www.camperrules.com/how-to-w...to%208%20gauge.
- states I should have no issues either
https://learnmetrics.com/30-amp-wire-size/
- again - states I should use 10/2 under 50 feet

Question 1: Will 10/2 work to go 34 feet to the Multiplus then back 34 feet to the main RV breaker box?
Question 2: Should I be using the same 10/2 Romex Lance used? or should I be buying the Ancor cable?

Note: I am placing both cables in a cable shroud and attaching it to the frame with the other wires running along the frame.

powercat_ras · 02-04-2023, 10:23 AM

10/2 w ground will carry 30 amps without overheating, the issue as you note is that under full 30 amp load it will have voltage drop of 0.06 volts per foot. So adding 64 feet of 10/2 will reduce line voltage at the WFCO box by 3.8 volts at full load worst case vs. whatever it was before, when using shore power. When AC is being generated by the inverter, it would be half that worst case and would be fine even with the 10/2.

The actual maximum current that a 30 amp circuit breaker will carry long term is 27 amps before eventually doing a thermal trip so the real world voltage drop is about 10% less.

Going to 8 gauge would cut that to 2.3 volts. I'd use 8 gauge. You have a lot of other voltage drops while on shore power already from the shore cable and from the voltage drop of the system providing power to the RV pedestal which is not great at many locations.

All that said you should look for a location much closer to your WFCO box if practical.

twinboat · 02-04-2023, 10:35 AM

Unless your planing on running everything in your RV on inverter power, you could create a sub panel.
Install a 25 amp breaker in your main panel and run that to and back from the inverter. Then set up a sub panel with the circuits you want powered by the inverter.

Captain8 · 02-04-2023, 03:45 PM

Quote:

Originally Posted by twinboat

Unless your planing on running everything in your RV on inverter power, you could create a sub panel.
Install a 25 amp breaker in your main panel and run that to and back from the inverter. Then set up a sub panel with the circuits you want powered by the inverter.

The MP is designed to run everything through it which them gives it UPS functions and other features.

OP you might want to consider upgrading to 6/2 with ground and using a 50amp cable. Even if you have 30amp breakers in your rig the 20amp extra can be used to charge the batteries and such.

Another idea is to put a plug instead of cable for shore and move it closer to your bed. I did this on my class A RV and put the plug on the back, also added a 15amp plug in tandem which I almost always just use. Having it in the back makes a nice breakaway from my extension cord when someone forgets to unplug from shore.

twinboat · 02-04-2023, 07:26 PM

Quote:

Originally Posted by Captain8

The MP is designed to run everything through it which them gives it UPS functions and other features.

OP you might want to consider upgrading to 6/2 with ground and using a 50amp cable. Even if you have 30amp breakers in your rig the 20amp extra can be used to charge the batteries and such.

Another idea is to put a plug instead of cable for shore and move it closer to your bed. I did this on my class A RV and put the plug on the back, also added a 15amp plug in tandem which I almost always just use. Having it in the back makes a nice breakaway from my extension cord when someone forgets to unplug from shore.

I agree it has a UPS function but it's only 2000 watts. If the A/C, water heater and microwave are on, it's going to fault out.

Captain8 · 02-04-2023, 08:50 PM

Quote:

Originally Posted by twinboat

I agree it has a UPS function but it's only 2000 watts. If the A/C, water heater and microwave are on, it's going to fault out.

Sure but you can disconnect from shore and not have AC shut off on you or anything else. Also it has power boost so if he's on 15amp he can get 2000w more watts so basically 30amp service.

lentineaz · 02-07-2023, 04:57 PM

First: Thank you for the replies

Second: If I disable Power Assist - I don't see any reason to upgrade to the 50 amp internally. Its still a 30 amp before the Multiplus.

Third: I am planning on using the Ancor Marine 8/3 placed in some conduit because I have to run in in the frame outside not inside the Rv.

DC side pictures; I have to clean up the V.E bus wires and such but I will get to that when I hook up the AC side:

https://imgur.com/ciUR6pc

Captain8 · 02-08-2023, 05:56 AM

30amps plus the power assist will give you about 50amps. Usually whenever you're using higher than 30 amps it's just for a few minutes like starting the ACs, running the microwave, etc. It's an amazing feature that makes everything just work.

Even if you don't upgrade the wiring I'd leave the power assist on. Your 30amp breaker will allow 5 or so amps additional for a bit before tripping so it can help with these things. Shore breaker does the same but it's further and you'll have the MP set to only allow 30amps which it'll actually only allow 27.5amps or so just to make sure it's under.

Captain8 · 02-08-2023, 05:58 AM

Why no cerboGX? It's like the best device ever and gives you everything you could ever ask for on your phone. Also what's that victron device on top of the batteries?

xc-mark · 02-08-2023, 03:32 PM

I would suggest you read the inverter install guide, it only suggest fine strand wire and FOR SURE NOT SOLID WIRE in the inverter connectors. I would suggest 8-3 SEO hard use cord and NOT romex! vibration and stranded wire will be more likely to hold a good connection on the type wire connectors on your inverter. this size wire is good for a 30 amp shore power , if you plan on do a full 50 amp upgrade to your shore power you would need 6-4 SOE cord. With RV with 2 roof AC units you will want the 50 amp upgrade!

The cerbo and touch 50 is a nice upgrade , at a bare minimum you will want the inverter controler , Not just the dongle. changeing your current limiting for shore power is necessary at times. Parks with bad voltage drop when it gets very hot I limit my shore power to 18~20 amps to keep shore power voltage above 105 volts. I let the solar and battery pick up the ballance of power needed for 2 AC units.

lentineaz · 02-08-2023, 10:28 PM

No reason to have a cerboCX - seemed like a bit much for me.

I will not be using solid Romex. Using Ancor Marine Wire. I use a generator and I never go to RV parks. Only reason I have solar is so I can be away from the RV and everything will stay running. Additionally, when I am working I only burn about 6amps an hour on so I wont strain my system very much.

My generator has a screen and I see the amps I am pulling at all times. I can monitor it again at the Multiplus.

I have a hard time justifying upgrading to the 50 amp when my generator can't even support that and that's how I've been living for 2 years.

@Captian8 I appreciate the advice on the PowerAssist. I was unaware I could tune it that low.

My old RV I had 400watts with a Renogy Controller and a SOK battery. Worked like a charm and ran all my 12v stuff forever.

Captain8 · 02-09-2023, 09:50 AM

cerboGX is like $230 on amazon, no need for the touch50 screen as it's the same on your phone. If you have internet in your coach you can see everything from anywhere on your phone all for free. A major feature is you can change the shore amp limit instantly so when I'm at home I click 15amp but when at CG I switch it to 50.

It works with Ruuvy temp sensors too so you can place them everywhere and monitor temps. Perfect for the fridge (make sure food doesn't go bad), wet bays (Incase of freeze), inside/outside and even I have one on my radiator. Not only does it show everything it logs it all so you can compare usages and everything. I know how much power I consume and solar input all in 15min increments and all exportable to excel.