Circuit Breaker for the SB5

Short Circuit Protection:
The P514 Power Supply that is supplied with the SB5 incorporates internal short circuit
protection that will shut down track power in the event of a short circuit. The unit will
attempt to re-energize the track every 3-4 seconds until the short is cleared. The Status
LED conveys status of the track power. The LED will ‘blip’ each time the P514 attempts to
restore track power, steady ‘on’ of the LED indicates track power is restored.

The circuit protection of the SB5/P514 is not intended to protect the booster from long term short circuits. Do not allow a short circuit to persist for more than 30 to 60 seconds or damage will result.

Therefore we strongly recommend an external circuit breaker like the EB1.

Click here to buy an EB1 direct from NCE


The default trip rating of an EB1 circuit breaker is 16ms. That is roughly 30 times faster than the standard booster overload trip time!

The reason you would add protection of some sort is that you don’t want the entire railroad to shut down if you have a short. You break it up into smaller pieces. All of our systems will only try to protect themselves and not your locos. Use the EB1 to divide up your layout and protect your trains! Think of this like the breaker panel in your house.

You can have a short circuit in a decoder but there is no guarantee it will trip a DCC circuit breaker or shutdown a booster.  Myth:  DCC circuit breakers protect decoders.  Fact:  DCC circuit breaker protect boosters.
The goal of the DCC circuit breaker is to protect THE BOOSTER by isolating the short locally within the breakers power district so the booster can remain powering the OTHER power districts to keep the other parts of the layout running.
For the DCC circuit breaker to act, a short circuit has to meet specific criteria.
 a) The short circuit current must be above the trip point of the DCC circuit breaker.
b) The short circuit current must last for a period of time.

You MUST use some form of Protection!




Was this article helpful?
0 out of 0 found this helpful
Have more questions? Submit a request