Article C5.19.5
DC-DC Unit HV DC Bus Protection
Technical Regulations
Article C5.19.5
DC-DC Unit HV DC Bus Protection
Chapter: C5
In Simple Terms
The DC-DC Unit (which converts electrical power in the hybrid system) must have a fuse to protect it, and sometimes needs a relay as well. These safety devices act like circuit breakers to prevent damage if something goes wrong with the electrical connections.
- A fuse is mandatory on the DC-DC Unit's high-voltage power line to provide protection
- Additional relay protection devices may be required depending on where the Energy Store is connected
- These protective devices isolate and protect the DC-DC Unit from dangerous electrical short circuits
- The protection covers both the positive (DC+) and negative (DC-) power poles
Official FIA Text
The DC-DC Unit HV DC Bus branch must have a DC-DC Unit fuse, and, additionally, DC-DC Unit relay(s) if connected on the ES side of the ES Main contactors. Those protective devices will insulate the DC-DC Unit from the HV DC Bus DC+ and DC- poles and protect the installation in case of short circuit.
dc-dc unithv dc busfuse protectionrelayhybrid system
2026 Season Regulations