You've hit on a crucial point that's often poorly documented in inverter manuals: the precise mechanism of the emergency stop function. Let's break down the manual statement and then discuss what's likely happening in the Sol-Ark 15K.

Analyzing the Manual Statement



"The (B, B) emergency stop pins of the Sol-Ark 15K-2P-N are an ordinarily open contact that triggers rapid shutdown (RSD) when closed." This clearly means you need to short the B/B terminals to activate the E-Stop/RSD. An open circuit on those terminals means everything is normal. "RSD will cut all power including the Sol-Ark’s internal power supply and stop all AC outputs." This is the key statement, but also the vague one. It tells us the result of the E-Stop: Cut all power including the Sol-Ark's internal power supply

This suggests the inverter completely shuts down, not just disables the AC output.

Stop all AC outputs

Confirms that the AC output is disabled.

What's Likely Happening Inside (Based on Industry Practices and General Inverter Design)

While the manual doesn't explicitly say "relay" or "contactor," it is highly probable that the Sol-Ark 15K uses a combination of both a control circuit AND physical components to achieve the emergency shutdown. Here's a common scenario:1.

Control Circuit Activation

When you short the B/B terminals, you're likely triggering a control circuit within the inverter. This control circuit then signals other components to shut down. This is almost certainly a solid-state device, not a physical contactor.2.

AC Output Disconnect

The control circuit almost certainly triggers

relays (or possibly solid-state relays, SSRs) on the AC output lines (both L1 and L2). These relays physically disconnect the inverter's AC output from the grid/load. This is to ensure that no AC voltage can be output, even if the inverter's internal electronics are malfunctioning. In this case, it's possible that solid-state relays are used, with no moving parts, but that's just speculation.3. Internal Power Supply Shutdown

The control circuit also deactivates the inverter's internal power supply. The exact mechanism for this varies, but it may involve:

A physical relay or SSR

Disconnecting the AC input to the power supply.

Solid-state switching

A more sophisticated design might use solid-state switches to cut off power to key components within the inverter, effectively shutting it down.

Why the Vagueness in the Manual?

Inverter manufacturers often avoid being overly specific about internal components for several reasons: Proprietary Design

They want to protect their intellectual property.

Design Changes

Inverter designs evolve. Specifying a particular relay in the manual would require constant updates as components are changed.

Complexity

A detailed explanation of the shutdown mechanism could be confusing for the average installer.

How to Confirm (if Critical)


Contact Sol-Ark Technical Support

This is the most reliable way to get a definitive answer. Ask them specifically if the E-Stop function uses physical relays or contactors to disconnect the AC outputs and shut down the internal power supply. If there are contactors/relays, ask for the specifications of those components.2.

Inspect with Power Off (and Qualified Personnel)

If you have the appropriate qualifications and training, and with the inverter completely disconnected from all power sources (PV, battery, and AC), you might be able to carefully inspect the internal components. Look for physical relays or contactors connected to the AC output terminals and the input of the internal power supply.

WARNING: This is dangerous if you don't know what you're doing. Do not attempt this without proper training and experience! Even when disconnected, capacitors inside inverters can hold dangerous voltages.3. Test with Caution (and Qualified Personnel)

Again, with proper training and experience, you could perform a controlled test. With a monitoring device (voltmeter) attached to the AC output terminals, activate the E-Stop. Listen for the audible click of a relay or contactor. The disappearance of voltage should be close to instantaneous, which is generally a sign of a contactor or relay opening.

WARNING: Exercise extreme caution when working with live electrical circuits.In Summary:

While the manual doesn't explicitly state it, it's very likely that the Sol-Ark 15K uses relays and contactors to physically disconnect the AC output and shut down the internal power supply when the E-Stop is activated. However, it's highly recommended* to contact Sol-Ark support for confirmation and detailed information on the components used. Flag for review