DC Cabling

DC Cabling

DC wiring includes the positive and negative conductors from the battery(s) as well as a disconnect device and over-current protection. Locate your battery(s) as close as possible to your inverter (or vice-versa) to reduce energy losses caused by cable resistance. Cables should be as short as possible (5-10 feet) and large enough to handle the required current, in accordance with the electrical codes or regulations applicable to your installation. The connectors on the inverter/charger are designed to fit up to 500 MCM crimp-on ring terminals (either AMP or ILSCO) or box connectors.

Do not route your DC wiring through an electrical distribution panel, battery isolator, or other device that will add additional voltage drops.

DC Over-Current Protection

Installation codes require over-current protection for battery cables, installed as close as possible to the battery, in the positive side of the circuit. The current rating of this DC fuse or circuit breaker must be large enough to allow the Prosine inverter/charger to operate your loads, but if the rating is too high, electrical codes will require you to use larger DC cables than you would otherwise have to. The fuse or circuit breaker must be rated for use on DC circuits. Fuses or circuit breakers rated only for AC service are not suitable for use on DC circuits and may pose a hazard. The wire size used between the inverter/charger and the fuse or circuit breaker must be sized to match the fuse or circuit breaker's current rating, in accordance with the electrical codes or regulations applicable to your installation.

The following table outlines the minimum DC cable size and maximum fuse size required for some common installation codes. There may be other codes and regulations applicable to your installation.

 

Marine Installation

RV Installation

Residential Installation

 

See footnote a.

See footnote b.

See footnote c.

 

 

 

 

 

 

 

Model

Wire SizeFuse Size

Wire Size

Fuse Size

Wire Size

Fuse Size

 

 

 

 

 

 

 

Prosine 2.5/12

# 2/0 AWG350A# 3/0 AWG

350A

350 MCM

350A

Prosine 2.5/24

# 4AWG175A# 3 AWG

175A

# 2/0 AWG

175A

Prosine 3.0/12

# 3/0AWG450A# 4/0 AWG

450A

500 MCM400A

Prosine 3.0/24

# 2AWG250A# 2 AWG200A

# 3/0 AWG

200A

 

 

 

 

 

 

 

a. Based on ABYC Recommended Practice E-9, 75C wire, no conduit. b. Based on the NEC, NFPA 70, Article 551, 90C wire.

c. Based on NFPA 70, Article 240 and 310, 75C wire, wire in conduit. If your installation code allows you to wire in free air, then the following table applies. NOTE: This table applies to residential installations only.

Model

Wire Size

Fuse Size

 

 

(Amps DC)

 

 

 

Prosine 2.5/12

# 3/0 AWG

350A

 

 

 

Prosine 2.5/24

# 2 AWG

175A

 

 

 

Prosine 3.0/12

250 MCM

450A

 

 

 

Prosine 3.0/24

# 1 AWG

200A

 

 

 

What the above tables do not take into account, however, is voltage drop associated with greater cable lengths. It is always best to use oversize cables to reduce voltage drop and improve inverter performance.

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Prosine Installation & Operation Guide