SSPC on fire

Thread Starter


Joined Dec 21, 2022
SSPC was burned.

The SSPC manufacturer said the A/S period is over and they can't tell us the inside details because of security.

I thought the cause was a short circuit in the outer line. (Because I got a picture of the outer line cut by force.)

But SSPC trip when overloaded, and when I put on a load right before the trip, they can't get past the temperature of 75°C, 167°F.

(+This product uses four types of SSPCs.)

Can short circuit cause SSPC Fire?

An old SSPC is being used, but 75°C, 167°F are temperatures within the specification, so I am not sure if the load just before the trip is the cause of the fire.

I want to read other people's guesses about the cause of the fire.

Or if the temperature within the specification can cause a fire.

(+ Trip and inrush currents also operated within the specification. )

Thread Starter


Joined Dec 21, 2022
There is a power distribution box that our company makes.

It contains several SSPC(Solid-State Power Controllers).

And there was a call that this box, which has been used for more than 10 years, had a fire.

When I opened the box, I could see that the fire started in the SSPC.

And the middle of the power cable was cut off, so it is suspected to be a short circuit.

But I thought it was strange that the short circuit caused too much current to flow to the element, and this caused the fire.

The SSPC has a built-in function (trip) that blocks when too much current flows.

Sending enough current to stop the trip does not exceed 75°C.

(When the rated current is 20 A, and the trip is triggered at 30 A. If 29.8 A is spilled for an hour, the temperature is 75°C.)

However, this temperature is within the operating range, so I wonder if this really can cause fire.

Can the SSPC cause a fire due to overload? Or do you know any other cases that SSPC catch fire?

You might want to provide some information about just what incident you are referring to.


Joined Jan 23, 2018
Solid State Power Controller is a broad category and the request is for help with one specific UNKNOWN DEVICE. So answering questions about an unknown device as part of an unknown system, possibly subjected to unknown abuse, is not a simple task.

Certainly operation beyond design limits can cause damage and overheating in any system. That would include operation beyond designed current or power dissipation.
Normally overcurrent protection is provided prior to any equipment.