Fuse/Circuit Breaker Sizing Guidelines

Installation

Because batteries can produce thousands of amps, you are required to install DC-rated fuses (or circuit breakers) that can safely withstand the short-circuit current batteries can produce.

To select the correct fuse type and size:

1.Determine the total cold cranking amp rating for your battery(s).

Note: The cold cranking amp rating of each battery is displayed on the battery case. If it is not, contact the battery manufacturer to find out.

For example:

•If you are using one battery to power your inverter and its rating is 500, the total cold cranking amp rating is 500.

•If you are powering your inverter with two batteries in parallel, and each has a rating of 500, the total cold cranking amp rating is 1000.

2.Once you have determined the total cold cranking amp rating of your batteries, identify the corresponding Ampere Interrupting Capacity (AIC) of the fuse or breaker required for your system by referring to Table 2.

Note: The AIC is the amount of battery short-circuit amperage that the fuse can safely withstand.

•If the Total Cold Cranking Amps indicate that the AIC is 2,700 amps or less, see Table 3 for the correct ANL fuse.

•If the Total Cold Cranking Amps indicate that the AIC is up to 200,000 amps or if you require a “code fuse”, see Table 3 for the correct Class T fuse.

Table 2 Cold Cranking Amps / AIC

Total Cold Cranking	Ampere Interrupting Capacity
Amps	(AIC)

650 or less	1500

651–1100	3000

over 1100	5000

Table 3 Fuse Ratings

Model	ANL Fuse	Class T

PROwatt SW 600	80 A	80 A

PROwatt SW 1000	150 A	150 A

PROwatt SW 2000	250 A	250 A

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Fuse/Circuit Breaker Sizing Guidelines

For example:

Total Cold Cranking

Amps

(AIC)

Model

ANL Fuse

Class T