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Small Cabin Forum / Off-Grid Living / Titan Solar Generator - Wiring Cabin
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OldMacDonnie
Member
# Posted: 5 Jan 2022 12:43
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Total newb here...

I have a question that I hope you all can help answer. I have a tiny cabin (10x16) that I've built on our property that is 100% off-grid. For clarity's sake, this cabin never has had power to it from any other source and never will. I've wired the cabin essentially the same as a house and the plan is to have the Titan feed into the sub-panel via its 125v/30amp outlet. My question is regarding the sub-panel. Do I need to run a grounding rod outside from the subpanel and do I need to use the bonding screw as well?
Cabin
Cabin
Titan Generator
Titan Generator


gcrank1
Member
# Posted: 5 Jan 2022 13:19
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Nice looking place!
Not sure, but I think with a service panel you need to do the ground rods, around here it is 2.
The panel likely has '2 legs', each 120vac intended to be fed from 240vac.
Your 'pwr-box' can be plugged into a proper, safe socket (RV inlet type) to feed the service panel.
If the pwr-box is 120vac it will only power up 1 leg of the two in the box unless you 'tie/jumper' between them. If the pwr-box puts out 240vac it would work just like grid power in; ie, no need to jumper the legs.
The panel should also be able to be fed the same way by plugging in a generator.
As to the bonding screw, I dont know, but iirc in this kind of feed off grid the bonding isnt used?

SCSJeff
Member
# Posted: 5 Jan 2022 13:20 - Edited by: SCSJeff
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I would still run a grounding rod for the subpanel. Depends on whether the Titan bonds N & G for the bonding screw. If it does NOT, then I would use the bonding screw in your subpanel.

Edit: Since the Titan does not have any GFCI receptacles, I'm guessing it does NOT bond N & G. But, you need to confirm.

OldMacDonnie
Member
# Posted: 5 Jan 2022 13:41
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Everything in the cabin will be 120vac, gcrank1, so I believe the subpanel I chose will only handle 120. At least that's what I think...kind of doing this seat-of-the-pants. The pigtail running into the subpanel from the Titan to the box is 10-2 metal clad so if I understand this correctly, the 3 wires in it will go to their respective lugs for hot, neutral and ground. If needed, I have a gas generator outside that I can run into this setup as well as I could just use the chargers for the Titan batteries too. Of course this would only be needed when it's cloudy as the 15x100w panels should easily keep up with this small of a cabin.

SCSJeff, I'll get with PointZero to confirm whether or not I should bond the Neutral and Ground in this setup. I'll go ahead with the single grounding rod that is required for this area.

This configuration may seem like overkill to many but I wanted a solar generator that was portable to use with a travel trailer when needed, at home and at this tiny cabin when we are there.

SCSJeff
Member
# Posted: 5 Jan 2022 13:48
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I've read good reviews about the Titan. Just pretty expensive

OldMacDonnie
Member
# Posted: 5 Jan 2022 14:09
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Yah, stupid expensive. If I wasn't using this in multiple scenarios I would have gone more of a DIY approach.

It is a pretty nice place gcrank1. Been a lot of work clearing the undergrowth, prepping the build site and now finishing the vision of what I had in mind. When I get this wrapped up in the next month or two I'll probably find myself going back to clearing out more areas of undergrowth and mapping out / cutting hiking trails. For some odd reason I find that enjoyable. Must be something wrong with me.

ICC
Member
# Posted: 5 Jan 2022 14:17
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If I understand what you have done in the cabin, then just to avoid confusion I would not refer to the service panel as a sub-panel. It is the only panel in the cabin, is it not? As the sole panel just call it the service panel. My reasoning is that by NEC a sub-panel never has a neutral-ground bond. The N-G bond is done at the main/only panel. The generator is simply a power source, much like a utility connection for all practical purposes.

There should only be one neutral-ground bond in a system like a home, RV, whatever. That should be in the main service panel.

Buy a receptacle tester to be sure of what the Titan has inside. I do believe it will NOT have a bond. It will likely use what is generally known as a floating neutral..

There are many brands of receptacle testers. Under $10 and handy to have.Here is one. Plug it into the Titan, or any generator power source. With power turned on the single light indicating an open ground indicates there is NO neutral-ground bond.

Then you should bond at the service panel and be safe.

FYI, IF you have an unbonded generator and want to use it with a neutral-ground bond you can make a cheater plug. Take a std electric 3 prong plug and wire the neutral to the ground prong with a short length of suitable wire. Plug that into one generator socket and the other becomes bonded as well.

**************

The presence or non-presence of a GFCI outlet has nothing to do with a neutral-ground bond. A GFCI will work correctly without there being any ground wire at all. Like you can install a GFCI in an old house that still has old circuits with only a hot and a neutral and the GFCI will provide protection. The GFCI only interrupts the power. It does not shunt power to ground or need a ground to function. As long as the GFCI test button trips the protection it is safe as far as what the GFCI is intended to do.

ICC
Member
# Posted: 5 Jan 2022 14:22
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You should install at least one ground rod connected to the service panel. It is advisable, required in some places, to use two ground rods, 8 ft long that connect to the service panel ground using a single conductor from panel to rod 1 and on to rod 2. Code is 6 feet separation but 15 to 20 feet is better.

No ground rod at the Titan or any other generator.

gcrank1
Member
# Posted: 5 Jan 2022 15:34
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Not to hi-jack, and since we are talking 'ground rods', is an old driven well pipe, say 2 1/2" and over 40' down, suitable as a ground rod to connect to?

ICC
Member
# Posted: 5 Jan 2022 16:34
Reply 


Probably.

The real answer can be had by measuring the resistance between that pipe and another rod/ground at least 6 feet distant. Should be 25 ohms or less. Lower ohms is better.

SCSJeff
Member
# Posted: 5 Jan 2022 16:59
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ICC,

Thanks for the clarification on the GFCI.

I was just going by my one inverter that has GFCI receptacles and also has the N/G bond.

Also, the GFCI receptacles in my cabin didn't operate correctly until I bonded my N & G. (They worked and the Test button worked, but a receptacle tester would not trip them)

ICC
Member
# Posted: 5 Jan 2022 18:31
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I learned that the ground was not needed for the GFCI to work from an electrician years ago when we had him doing some updates in a barn that had old knob and tube wiring.

The GFCI compares the current flow in the hot and the neutral lines. If it senses a difference as small as 4 or 5 milliamps it trips in less than 1/10th of a second. It is still better to have the ground wire but that is not firectly related to GFCI.

OldMacDonnie
Member
# Posted: 5 Jan 2022 18:38
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Here's the response from PointZero:

"Because the Titan is a floating neutral generator, you can bond the neutral and ground in the subpanel. If it was a subpanel to a main panel then you would not bond the neutral but since this subpanel is acting as the main panel for your cabin you should be able to bond the neutral at the panel."

Aside from my use of "subpanel" in lieu of a "service panel", the answer is to bond the N & G.

SCSJeff
Member
# Posted: 5 Jan 2022 21:06
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OldMacDonnie
Member
# Posted: 6 Jan 2022 21:39 - Edited by: OldMacDonnie
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I'm back looking for some more help.

I've been trying to clarify online exactly where each of the 3 feed wires from my 10/2 pigtail go in my 120v service panel. I've attached a picture of what I believe to be correct, where a jumper is used. Anyone here able to confirm if this is correct or is this sort of like a 240v configuration? Or do I just connect the hot wire to one of the lugs where the breakers attach and leave the other open?

In some ways I'm using ideas from RVs to set this cabin up and the video at the link below shows how they set up a 120v panel with a jumper.

https://www.youtube.com/watch?v=VbYGUkn7PyA
10-2 Feeder
10-2 Feeder


ICC
Member
# Posted: 6 Jan 2022 23:37
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If you want to use all the breakers you need to jumper the two bars together. #10 is good to 30 amps. I have no idea what he power unit can supply, but keep that in mind

How are you planning on connecting this panel to the Titan? If there are two outlets on it you could always use two cables, one to each half of the panel breakers.

gcrank1
Member
# Posted: 7 Jan 2022 10:23 - Edited by: gcrank1
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The face on that Titan looks like you have maybe a 30a outlet with plug/armored cable running up through a box?
120vac @ 30a into the service panel to one bar, jumper that to the other and you have both sides to use BUT you are limited to the power provided of 30a.
Thats one 15a outlet per side, only one of the duplex receptacles used.
Thats also two 15a outlets off one side, same limitation.
How many circuits did you plan on using?
Im total off-grid. I have high draw stuff I run off the genny and low draw stuff off the solar/bat/inverter, all 120. I could see wiring one side of the ser. panel as the genny powered and the other off the Titan.

OldMacDonnie
Member
# Posted: 7 Jan 2022 10:26
Reply 


The Titan has a 30amp 120v RV outlet that I will plug a pigtail into that feeds into the service panel.

I’ve been very careful to select lighting and appliances that have power consumption well within the Titan’s ability to support.

OldMacDonnie
Member
# Posted: 7 Jan 2022 10:41
Reply 


@gcrank1, I have 7 circuits wired but wasn’t planning on using them at the same time. Just had outlets wired if I wanted them in different parts of the cabin. What you are saying though has me re-thinking this (yet again). In my figuring of all this, I was more focused on watt-hour consumption.

gcrank1
Member
# Posted: 7 Jan 2022 11:01
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7 circuits! Do you have more than one outlet on each circuit?
For off grid living 'power conservation' is the 1st approach, so wh consumption is prudent and appropriate.
The combined power used on all circuits cant exceed the Titan's 30a outlet.

OldMacDonnie
Member
# Posted: 7 Jan 2022 11:16
Reply 


In some cases, yes. I never intended to have them all available at one time, just for convenience so as to not have to run extension cords everywhere. I can do what I want with 30amps though.

OldMacDonnie
Member
# Posted: 7 Jan 2022 14:34
Reply 


Just to make sure I'm correct here, I can have multiple (more than 2) 15 amp circuit breakers wired and as long as the collective amp draw across all circuits doesn't exceed 30 amps I'm ok. Is that correct? When I do exceed 30 amps, the circuit that exceeds that limit will pop that respective circuit breaker off, correct? I ask because some of these circuits will likely only have less than 5 amps on them at most.

For example all lights are LED and will collectively pull 3 amps, but they are on 2 different circuits with 15 amp breakers. Also have a device that is plugged into a 15amp outlet but drawing 1.2 amps on one circuit, another plugged into a 15 amp outlet drawing 11 amps on another circuit. So with these 4 primary circuits, I have a total amp draw of 15.2 amps, well below 30 amps available with the Titan.

Sorry for all the questions. I'm completely learning this as I go.

curious
Member
# Posted: 7 Jan 2022 14:59
Reply 


Quoting: OldMacDonnie
When I do exceed 30 amps, the circuit that exceeds that limit will pop that respective circuit breaker off, correct?

No. If you do not exceed the rated limit on any single breaker in the panel, none of those breakers will trip. If you draw a total greater than 30 amps, then whatever protection the Titan is equipped with should trip and that will shut down everything downstream.

OldMacDonnie
Member
# Posted: 7 Jan 2022 15:13
Reply 


Bottom line then is stay below 30amp total draw across all circuits at any given time (and below the limit of any single breaker on any given circuit) and all should work fine. Correct?

gcrank1
Member
# Posted: 7 Jan 2022 15:50
Reply 


Wouldnt it be better to have a 30amp (or even a 25?) CB 'main' in the ser. panel to trip rather than rely on whatever cheap (I have come to expect cheap components are often used) CB in in the Titan?
Just like a home panel, youd have a main and the individual circuit protection. Only diff here is your Titan takes the place of the grid feed.

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