Busbars & studs – professional power distribution for on-board systems and vehicles
Busbars and studs are the backbone of every professional on-board installation. They connect batteries, main switches, fuses and loads into a structured, reliable DC distribution system – in 12, 24 and 48 V systems on boats, yachts, motorhomes, expedition and special vehicles. The range includes copper busbars, power distributors, feed-through studs and terminal blocks – from philippi and Blue Sea Systems, for currents from a few amps up to 1000 A.
In brief: Busbars bring several cable outputs together on a common potential – positive or negative – for clean, clear and standard-compliant power distribution without unnecessary connection points. How to choose and install the right busbar is explained in the guide Busbars for boats & campers.
Why busbars instead of individual wiring?
In professional on-board systems, busbars are used to connect several loads, battery feeds or return lines at a common point. The advantages over direct individual wiring: minimal contact resistance thanks to solid copper conductors, a clear and easy-to-maintain installation, lower fire risk through structured cable routing, and compliance with DIN EN ISO 13297.
All busbars & studs at a glance
SMS series – compact busbars for small and medium systems
SMS busbars are the compact standard solution for smaller systems and negative distribution points, in single and double versions:
| Model | Design | Connections | Typical use |
|---|
| SMS 7 | Single | 2 × stud 5 mm, 5 × screw 4 mm | Negative distribution, small systems |
| SMS 14 | Double | 2 × 2 studs, 2 × 5 screws | Double negative distribution |
| SMS 22 | Single | 2 × studs, 20 × screws | Larger distribution points |
DualBus series (Blue Sea Systems) – positive and negative in one unit
DualBus busbars allow double-pole connection of loads on a single unit. Tinned copper, voltage range max. 48 V DC.
| Model | Design | Connections | Continuous rating |
|---|
| DualBus 2701 | 2-pole | 5 loads (10-32 screws), 2 feeds (1/4" studs) | 100 A |
| DualBus 2702 | 2-pole | 2 × 10 screw terminals Ø 4 mm | 100 A |
Busbar BS 2305 (Blue Sea Systems) – standard for medium currents
Tinned copper with 4 threaded studs Ø 4.8 mm, voltage range max. 300 V AC / 48 V DC, continuous rating max. 100 A AC/DC, dimensions (W × H × D) 107 × 23 × 32 mm. Also available with protective cover.
PowerBar series (Blue Sea Systems) – for the highest currents
Solid tinned copper bars with 3/8" studs for anchor windlasses, bow thrusters, inverters and other high-current loads, voltage range max. 48 V DC:
| Model | Studs | Screw terminals | Continuous rating |
|---|
| PowerBar 2020 | 2 × 3/8" (9.5 mm) | – | – |
| PowerBar 2107 | 8 × 3/8" (9.5 mm) | 4 × Ø 4 mm | 545 A AC / 600 A DC |
| PowerBar1000 1990 | 8 × 3/8" (9.5 mm) | 5 × #10-32, 11 × #8-32 | 1000 A |
| PowerBar1000 1991 | 12 × 3/8" (9.5 mm) | 5 × #10-32, 11 × #8-32 | 1000 A |
| PowerBar1000 1992 | 8 × 5/16" (7.9 mm) | 5 × #10-32, 11 × #8-32 | 1000 A |
| PowerBar1000 1993 | 12 × 5/16" (7.9 mm) | 5 × #10-32, 11 × #8-32 | 1000 A |
MSS 9 – negative busbar for large cross-sections
For distributing battery feeds and outputs to anchor windlass, bow thruster and other loads. Nominal cross-section 300 mm², galvanically nickel-plated copper bar on plastic insulating supports, connections for max. 4 × 95 mm² (M8) and 5 × 25 mm² (M6). Dimensions L 238 × W 39 × H 42 mm.
EMS 6 – negative busbar for the Power Install System 250
6-way negative busbar rated 250 A, all studs M10, dimensions L 212 × W 40 × H 50 mm – the central negative distributor in the Power Install System.
SSP power distributors – studs and screw terminals combined
| Model | Studs | Screw terminals |
|---|
| SSP 1/8 | 1 × Ø 9.5 mm | 8 × 6.3 mm |
| SSP 2 | 2 × Ø 9.5 mm | 2 screw studs |
DFB feed-through studs – connections through bulkheads and panels
DFB with 8 mm stud: stud on both sides, mounting hole Ø 17.5 mm, IP 66, front W 32 × H 51 mm, black. DFB with 10 mm stud: mounting hole Ø 17.5 mm, IP 66, in black and red for clear polarity identification.
Terminal block and mounting studs
The screw-on terminal block for 6.3 mm blade connectors offers 3 separate potentials with 4 slots each – for small loads, sensors and control units. M10 mounting studs are available individually for replacement and expansion.
Material: tinned or nickel-plated copper
The busbars are made of solid copper, the metal with the best electrical conductivity among technical materials. Depending on the model, the surface is tinned (DualBus, PowerBar, BS 2305) or nickel-plated (MSS 9). Both provide lasting protection against corrosion from salt water and humid air – a decisive advantage over bare copper or brass in marine use.
Frequently asked questions about busbars & studs
What is the difference between a busbar and a power distributor?
A busbar connects several cable outputs of the same potential, positive or negative, via a solid copper bar with studs or screw terminals. A power distributor such as the SSP 1/8 combines one large feed stud with several smaller screw terminals. It is similar in principle but more compact and suits distribution points with many small loads.
Which busbar is suitable for an anchor windlass or bow thruster?
For high-current loads such as anchor windlasses, bow thrusters or inverters, the PowerBar busbars are suitable, the PowerBar 2107 with up to 600 A DC and the PowerBar1000 with up to 1000 A continuous, as is the MSS 9 negative busbar with 300 mm² nominal cross-section and connections for cable lugs up to 95 mm². Each outgoing cable is fused separately.
Why are feed-through studs available in red and black?
The colour shows the polarity: red marks the positive pole, black the negative. This makes connections easy to tell apart safely, even in cramped spaces and poor light. It prevents reverse-polarity mistakes during installation and makes later troubleshooting or expansion of the system easier.
Which voltages are permitted?
Most busbars in the range are designed for DC voltages up to 48 V and are therefore suitable for 12 V, 24 V and 48 V systems. The BS 2305 is also rated for 300 V AC and can therefore be used on the 230 V side. The specifications on each product page are decisive.
Are the busbars suitable for lithium systems?
Yes. Solid copper conductors and continuous ratings up to 1000 A make the busbars suitable for lithium battery systems with high charge and discharge currents. What matters is that stud size and rating match the cross-section of the battery cable and that every outgoing cable is fused according to its cross-section.
What does IP 66 mean for the feed-through stud?
IP 66 means complete protection against dust and against powerful water jets from any direction. The DFB feed-through stud is therefore also suitable for areas exposed to spray, for example to route cables through outer walls, bulkheads or battery boxes without compromising the seal of the partition.
