Question about hard wiring to an inverter with GFCI outlet

questoverland Registered Users Posts: 1
Hello, I tried searching, but couldn't quite find the answer I'm looking for, so here goes.

I have a 1500W Samlex inverter (Samlex Solar PST-1500-12 PST) hooked up to a house battery bank in a van. The inverter chassis is grounded to the van (as per Samlex instructions). Everything works fine with this very simple setup and I use the inverter by plugging in my devices (hot water kettle, computer, whatever) directly to the GFCI outlet built into the inverter.

However, I would like to hardwire in a few outlets (all on the same circuit) in some other places in the van. My understanding is if I was wiring up a circuit in a house and the first outlet was GFCI protected, then the other outlets on that circuit would be as well. My question is, when I hard wire to the inverter, am I bypassing the GFCI outlet that is there and thus I should install a GFCI outlet closest to the inverter, or can I just wire in regular outlets since they are downstream from the built-in GFCI outlet.

I've poured over the manual and I have found this:

RISK OF ELECTRIC SHOCK. When this unit is installed in vehicles and hard-wiring connection is used to feed the AC output of the inverter to the AC Distribution Panelboard / Load Center in the vehicle, it is to be ensured that Ground Fault Circuit Interrupter(s) [GFCI] are installed in the vehicle wiring system to protect all Branch Circuits.

But I'm not hard wiring from this unit to a AD Distribution Panelboard/Load center. 

Please let me know if anything isn't clear.

And thank you for your response.


  • BB.
    BB. Super Moderators, Administrators Posts: 33,473 admin
    On my phone, so short answers.

    GFI is there to reduce the chance of electrocution from AC hot to earth or other ground (like your van sheet metal).

    It will not protect against you touching black to white (hot to neutral) and getting shocked.

    If you look at the back of the GFI outlet, you can connect to the AC input and no GFI protection. Or connect to the GFI output terminals, and the one GFI will protect all of your AC wiring.

    GFI is primarily for keeping humans from getting electrocuted when working around water (wet hands, standing in puddle, using tools/hair dryer around sink and tub.

    I like 2 or more GFI circuits if one is for lighting and the other for appliances. If an appliance trips the appliance GFI, the AC lighting will stay on, rather than plunging you into darkness at the worst possible time.

    A van is always "near wet" at times (rain, swimming, cooking).

    Should you always use GFI? That is your call. It is cheap protection that will never or almost never trip if you use normal caution and your appliances are in good shape.

    If you had (example) hard wired AC LEDs for lighting and AC outlets for other stuff... not having the AC hard wired LEDs protected by GFI is a normal installation.

    There is another question "is the AC neutral wire (white wire) bonded to inverter/van chassis ground? TSW (true sine wave) inverters typical have the neural+ground bonding (in theory, it is safer)

    What are your thoughts? Grounding and GFI is a complex issue.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    edited May 2019 #3
    I Take it the inverter can be hard wired, it would be easy enough to just hard wire an outlet, then use the 'test' button on the GFI and see if the hardwired circuitry is on the same loop as the outlet on the inverter. If it is outlets on the GFI and outlets hard wired will be disconnected.

    Some inverters have a neutral-ground bond that can be removed, it will be where you hard wire the inverter.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former, 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
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  • Tecnodave
    Tecnodave Registered Users Posts: 437 ✭✭✭✭
    Most of Samlex inverters are built by Cotek, I'm not familiar with your particular model but on most there is a screw on the bottom of the unit that establishes a neutral to ground bond. This is clearly labeled as to exactly what it does. It's marked with a label.  Every AC electrical system should be "bonded" at one point and one point only in the system. This ground bonding makes sure that neutral (white) wire will not have voltage on it.  Do the ground bond at the inverter. The built in GFCI device will protect all devices plugged into it and any outlet connected to the output terminals of the GFCI. If you wire the external circuit to the input side of the GFCI down stream devices will not be protected by the built in GFCI and you will need an external GFCI to protect the external circuit. Don't wire two GFCI's in series, they will nuisance trip.
    Most of these inverters have a hardwire option where the internal GFCI is removed and a plate with cable clamp is installed in its place. I order mine that way. 
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