High current protection

High-current protection for main cables, windlasses and inverters

Main cables, anchor windlasses, bow thrusters and inverters need protection that carries high currents and disconnects safely in a short circuit. For this, philippi supplies SHB bolt-down fuses, Class T and strip fuses with matching holders, and resettable circuit breakers, from 25 A to 600 A.

In brief: The main fuse belongs as close as possible to the positive post, no more than 17.8 cm away (ABYC E-11). With lithium batteries, only the SHB bolt-down fuse or a Class T fuse is permitted at the post.

The cable configurator works out which fuse suits your cross-section in one step. The page Fuses on boats gives an overview of all designs.

The products at a glance

• SHB bolt-down fuse (MRBF): 30 to 300 A, M8 stud, 58 V DC, 10 kA breaking capacity. On the ABH 1 holder directly on the battery post or in the BS 5196 triple holder (up to 300 A) close to the post.
• Class T fuses: 20,000 A breaking capacity at 125 V DC, holders for 110 to 200 A and 225 to 400 A, fuses up to 600 A. The main fuse for large lithium banks.
• STS strip fuse with SHD holder: ceramic housing with inspection window, M10 connection. Proven and economical for main cables with lead-acid, AGM and gel batteries.
• ANL, MEGA and MIDI fuses with holders: fuse holders for ANL fuses up to 300 A and up to 750 A (32 V DC, transparent cover), FSM MEGA strip fuse 100 to 300 A (48 V DC, 1,000 A breaking capacity) in the SH 7721 holder, STM MIDI strip fuse 30 to 125 A (32 V DC) in the SHM 1 (up to 50 A) and SHN (up to 125 A) holders. SH 7721 and SHN are ignition protected to ISO 8846 and rated IP 66.
• 8345 series circuit breaker: hydraulic-magnetic, 40 to 160 A, 80 V DC, tripping independent of ambient temperature. Switches and protects in one device, ideal for anchor windlasses.
• TCB high-current circuit breaker: 25 to 100 A, 48 V DC, IP 67, with manual operation. Not for starter motors.

Which protection for which application?

Frequently asked questions

How far from the positive post may the main fuse be?

No more than 17.8 cm according to ABYC E-11, ideally directly on the post. The cable section before it is unprotected in a short circuit; that is why the SHB bolt-down fuse on the ABH 1 holder sits directly on the post.

Which protection do I need with lithium batteries?

At the post, only the SHB bolt-down fuse (10 kA) or a Class T fuse (20 kA). Lithium banks deliver very high currents in a short circuit, which other designs cannot disconnect safely.

Circuit breaker or fuse?

An 8345 series circuit breaker can be reset after tripping and replaces main switch and fuse in one device. Fuses are cheaper but have to be replaced after they blow.