Blue Sea 2105-BSS
2 studs · 12 screw terminals
Two 5/16-18 terminal studs plus twelve #10-24 screw terminals provide both high-current connections and smaller circuit attachment points.
Recommended insulating cover: 2718-BSS.
Blue Sea MaxiBus 250A Busbars: Studs, Screws & Covers
Blue Sea's 250A MaxiBus bars offer different connection arrangements for battery cables and electrical distribution. Some use only 5/16-inch studs, while others combine main studs with smaller screw terminals. Selecting the correct busbar and cover starts with the number and type of wires, their terminations and the installation's electrical requirements.
Stud-only versus combined stud and screw terminals
Two main studs plus screws2105 has two 5/16-18 studs and twelve #10-24 screw connections; 2128 has two of the same studs and six screw connections. Select based on required terminal positions and space.
Stud-only distribution2126 supplies six 5/16-18 studs, while 2127 has four. Both omit the smaller #10 screw terminals found on the mixed-connection designs.
Cover size mattersBlue Sea specifies insulating cover 2718 for 2105 and 2126; cover 2719 is intended for 2127 and 2128. Match the exact MaxiBus MPN rather than assuming the covers are universal.
Electrical installation: All four models are specified at 250A continuous and up to 48V DC or 300V AC. The manufacturer lists tin-plated copper bus conductors, 5/16-18 terminal studs and a glass-reinforced insulating base. Total system protection, wire ampacity, fuse selection, clearances and regulations must also be followed. A 250A busbar does not remove the need for proper overcurrent protection.
MaxiBus 2105, 2126, 2127 and 2128 terminal chart
The chart shows the actual manufacturer's stud and screw counts. All studs use 5/16-18 threads and mixed-model screw positions use #10-24 fasteners. Blue Sea specifies 132 in-lb stud torque and 23 in-lb screw torque where fitted; follow the exact manufacturer's installation instructions.
| MPN | Studs | Screws | Continuous rating | Cover MPN | Product |
|---|---|---|---|---|---|
| 2105-BSS | 2 | 12 | 250A continuous | 2718-BSS | View |
| 2126-BSS | 6 | 0 | 250A continuous | 2718-BSS | View |
| 2127-BSS | 4 | 0 | 250A continuous | 2719-BSS | View |
| 2128-BSS | 2 | 6 | 250A continuous | 2719-BSS | View |
Compare the four Blue Sea busbars
Each product image and link connects to the exact UsedRVParts listing. Confirm wire-lug diameter, terminal placement and the required protective enclosure.
Blue Sea 2126-BSS
6 studs · 0 screw terminals
Six 5/16-18 studs for multiple ring-terminal cables; unlike 2105 it has no smaller screw terminal positions.
Recommended insulating cover: 2718-BSS.
Blue Sea 2127-BSS
4 studs · 0 screw terminals
Four 5/16-18 studs in a shorter MaxiBus layout; use the designated 2719 insulating cover.
Recommended insulating cover: 2719-BSS.
Blue Sea 2128-BSS
2 studs · 6 screw terminals
Two 5/16-18 studs and six #10-24 screw terminals; smaller mixed-connection version of the MaxiBus arrangement.
Recommended insulating cover: 2719-BSS.
Choose the corresponding MaxiBus cover
The two insulating covers serve different busbar groups. They are separate products; confirm the cover's installation and access needs.
Blue Sea 2718-BSS
Fits 2105-BSS and 2126-BSS
Insulating cover matched to the longer two MaxiBus layouts.
Blue Sea 2719-BSS
Fits 2127-BSS and 2128-BSS
Insulating cover matched to the shorter four-stud or two-stud/six-screw layouts.
Blue Sea MaxiBus questions
Do all MaxiBus 250A models have four terminals?
No. The connection layout varies: 2105 has two large studs and twelve screws; 2126 has six studs; 2127 has four studs; and 2128 has two studs and six screws.
Does cover 2718 fit the four-stud 2127?
No. Blue Sea lists cover 2718 for 2105 and 2126, while 2719 fits 2127 and 2128.
Are 2105 and 2128 the same model?
Both combine two large studs with small screw positions, but 2105 has twelve screw terminals and 2128 has six. They also use different insulating covers.
Does the 250A rating mean all circuits can draw 250A individually?
No. The rating is the manufacturer's continuous rating for the busbar. Total combined current, terminal connections, installed conductors and overcurrent protection must all stay within their specified limits.
Can I use an uncovered busbar in a boat?
Follow the marine electrical installation requirements for the location, insulation and protection from accidental contact. Blue Sea offers covers for these MaxiBus models to reduce the risk of exposed live terminals.
Other electrical distribution guides
- Blue Sea 2300, 2301, 2302 & 2303 Common Busbar Guide
- RV Battery Compartment Fuse, Switch, Relay & Busbar Identification
Disconnect all electrical power before installation. Use appropriately rated wiring, circuit protection, connectors and mounting hardware in accordance with the Blue Sea installation instructions.
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