Consumer protection

Cable protection for consumers on board

Every cable in the on-board system is fused according to its cross-section. Fuses and circuit breakers thus protect cables and consumers from short circuits, overload and cable fires, in line with ISO 13297.

In short: the main fuse sits no more than 17.8 cm from the positive terminal (ABYC E-11), ideally directly at the terminal. Behind it, every circuit is fused individually at the switch panel or distribution, according to its cross-section.

What ISO 13297 requires

• All cables leaving the battery are fused according to their cross-section.
• The main fuse sits as close as possible to the battery; the section in front of it is unprotected and is kept short and mechanically protected.
• Downstream circuits with smaller cross-sections get their own fuses at the switch panel or distribution.

How each consumer is protected

Circuit breaker, strip or bolt-down fuse?

Circuit breakers can be reset after tripping and suit safety-relevant consumers and the feed to the switch panel. Strip fuses are proven and economical. SHB bolt-down fuses are made for high currents directly at the terminal. With lithium batteries, only SHB or Class T are permitted at the terminal.

The cable configurator calculates which fuse suits your cross-section. All fuse types compared: Fuses on board.

Frequently asked questions

Where is the main fuse installed? No more than 17.8 cm from the positive terminal, ideally directly at the terminal. This keeps the unprotected cable section as short as possible.

How is the right fuse size determined? By the cable cross-section: the rated current lies above the continuous current of the consumer and below the current-carrying capacity of the cable. The fuse protects the cable, not the device.

Do bilge pumps need separate fusing? Yes. Bilge pumps and other safety-relevant consumers are connected directly to the battery with their own fuse, so they work even with the main switch off.

Does ISO 13297 also apply to motorhomes? The standard applies to small craft. Its principles, main fuse close to the battery and every cable fused by cross-section, apply equally to motorhomes and expedition vehicles with 12 or 24 V systems.