Gdetrailer wrote:
larry cad wrote:
Gdetrailer wrote:
mr_andyj wrote:
Ground is ground. 2 amps is not a concern, but higher amperage might burn out the little tiny thermostat wire, not a concern here. Ground is ground, so if ground is issue with your pwm then any ground will be an issue. The steel camper frame is ground also, the entire frame of the camper is ground, all the ground wires are ground, they are all connected to the frame and to the negative post on the battery, ground is common to everything.
The only concern, as stated, is how much amperage will be flowing through your chosen ground wire.
I dont think there would be concern with your thermo wire, but try it, if it works then it works, job done.
Ground WIRE is not always "ground".
Yes it is!
That would be a blatant disregard of proper electrical wiring and a violation on NEC rules.
Can you please list the specific "NEC rule" that would be violated?
120V ground wires must terminate in the 120V breaker box on the ground buss. Yes, the ground buss must be bonded to to trailer frame but the 120V wiring has the potential for 120V currents which can cause voltage potentials on any of the ground wires that can cause issues like GFCIs false tripping or even higher voltage potential than 12V on your 12V system.
Gibberish! Voltage and Potential are the exact same thing. Voltage is potential.
The remainder of your comment makes no sense.
120V systems ground WIRE and 12V systems ground WIRE should never be exchanged or substituted or mixed.
We are back to "ground IS ground"
I would also not recommend using the furnace T stat wires for 12V ground as the "ground" you find there goes through the furnace control board and will no longer be at ground potential when the T stat calls for heat.
Wrong
Since there is no real 12V ground available OP will need to get creative on pulling an extra wire for the ground. If the location is close to wall trim you might be able to remove the trim carefully and carve out or drill a hole to thread the wire through the wall stud. Check at floor level to see if you can fish a wire from the floor up. Often you can drill holes just large enough to thread the wire but not too big to cause major damage that can't be hidden with some trim.
This is the closest you came to a sensible comment
Playing dumb is not an excuse.
NEC and "Common Sense" (yes, I realize Common Sense is dead but he was much smarter than anyone else on this planet) requires "separation" between "low voltage" items and "High voltage" items.
12V is considered and recognized as "low voltage" by NEC.
120V is considered and recognized as "high voltage" by NEC.
NEC requires "low voltage" and "high voltage" wiring to not be in the same space. You can plainly see this if you open up the breaker and fuse panel. All 120V wiring is in a separated compartment from the 12V wiring.
There is no DIRECT connection of the 120V wiring to the 12V wiring inside the breaker and fuse panel.
all 12V DC negative ground wiring is typically done outside of the breaker and fuse panel, all of the 12V negative ground wires will be found bunched together outside the panel under one huge wire nut. Under that wire nut one of the grounds is run to the trailer frame..
The 120V side, all grounds must terminate on a fully isolated ground buss bar, one of those wires will then run on its' own run separate from the 12V ground to the trailer frame.
While you might be "technically correct" that a 120V ground wire is at battery negative potential, it isn't what it was designed for or how it should be used.
The reality is the 120V ground wire is a safety ground for your 120V items, as such it has the potential to be carrying 120V voltages and currents under a fault situation.
The potential for 120V currents on the 120V safety ground is the reason in new builds that 240V items are no longer allowed to be wired as 2 HOT and only a safety ground and now are required to provide a Neutral wire.. In the old 3 wire scheme, things like driers would use the safety ground as a neutral for the motor and timer..
You might be right depending how the thermostat is wired in that the thermostat could break the connection to ground, but that seems unlikely. The ground should not go through circuitry, only the 12+, but without seeing the wiring exactly nobody knows... Technically the thermostat wires are not either positive or ground, they are just out-and-back and can be reversed as all that is happening is that the circuit is connected or not, nothing more, thermostats are an on/off switch, nothing more.
You might be wrong about ground not being ground.
We are talking about 12v DC current, not AC current. Do not connect DC items to an AC wire, some things are just a given in these discussions, some common sense applies and can go unstated. Do not look directly into the sun!
In AC wiring there is a Hot and a Neutral (and a ground). Often the Neutral is grounded (at the panel on 3-wire circuits), but never assume everything is wired correctly. Switching Hot and Neutral will do nothing to affect the working of the appliance, but will create a shock hazard as the Neutral and the ground are common at some point. Ask me how I know....
Usually, in all cases I have come across, in an RV or camper the White wires are ground wires, not the black. However, a technician might use a scrap piece of any color, black or white, to patch in positive or negative feed. In general, the long runs of White wire should always be ground. Do not assume this the rule for inside of an individual component's case; the furnace might have internal wiring that does not use color codes common to Rv's. White Ground only applies to the build-out of an RV, not everything and every item.
AC wires will be grounded to the frame the same as the DC wires. As you say, probably not at the same connection point or in the same box, but AC Neutral is connected to the DC ground, and AC ground on the frame. This should not be a concern at al
