Ring terminal connectors are essential for connecting the power supply cables of devices or appliances to the DC battery system in your camper. They feature a ring head that fits over the terminal stud of a battery or busbar. However, the quality of the electrical connection and power delivery to your circuits depends on the kind of ring terminal connector you use.
Sizing matters more than many DIY installers realise. The inner diameter of a ring terminal's central hole determines compatibility with battery studs or busbar bolts, but the outer diameter is also critical in preventing short circuits and arcing.
If you're planning to wire accessories in your campervan, caravan or RV, this article discusses the key features that define the best ring terminals on the market. This will help you select connectors that provide a secure connection with your circuit wires and ensure consistent, reliable performance.
What Are Ring Terminals Used For in Campervans, Caravans and RVs?
Ring terminal connectors (also known as O-ring connectors or eyelet terminals) are primarily for connecting electrical wires to battery studs or terminal bolts on busbars, fuse blocks or circuit breakers. Four common scenarios where you will use them in your camper wiring include:
- Connecting the positive power supply wire of a device or appliance to a battery terminal, busbar, fuse block or circuit breaker.
- Connecting the negative power supply wire of a device or appliance to a battery terminal or busbar.
- Connecting the earth (ground) wire of a device or appliance to the common ground point (bolt or busbar) in your camper.
- Connecting an ignition wire to the dedicated terminal bolt of a DC fuse block (applicable to select advanced fuse blocks).
As a long-time caravanner, RVer or boondocker, you may have twisted a stripped wire end onto a battery stud or busbar terminal bolt to make a connection. However, twisted wire connections are highly prone to intermittent connectivity or electrical failure due to loose connections. Stranded-wire cables used in DC connections also pose a high risk of electrocution or short circuits if even one strand is exposed and accidentally contacts your skin or an opposite terminal.
Therefore, always use O-ring connectors when wiring circuits to a battery or busbar. A properly terminated wire will contain all strands within the barrel end, and the "O" ring end guarantees a stable connection to the battery or busbar terminal.
What Are the Parts of a Ring Terminal Connector?
The basic structure of ring terminals consists of four main components: conductor, connection end, wire barrel and insulation.
- Connection end: As the name suggests, this is the part that connects to a battery stud or terminal bolt on a busbar, fuse block or circuit breaker. It is a flat, washer-like ring with a central hole that slips over the stud or bolt.
- Barrel end: This hollow tube houses the stripped end of the wire being terminated. Its internal diameter varies depending on the compatible wire gauge.
- Conductor: The core component that enables electricity to flow between the terminated wire and the connected battery, busbar, breaker or fuse block. It typically consists of conductive metal, with the connection end on one side and the barrel end on the other.
- Insulation: A non-conductive sleeve encasing the barrel end. This prevents accidental contact with the conductive metal, reducing the risk of electrocution, short circuits or damage from environmental elements.
What Makes the Best Ring Terminals for Camper Wiring Connections?
The materials and craftsmanship of ring terminals vary, as does their size. At Campervan Builders, we offer high-quality ring terminal connectors that ensure stable, reliable and safe electrical connections with battery, busbar or fuse block terminals. Here are the features to look for.
A Highly Conductive, Durable Copper Conductor
The conductor is the backbone of a ring terminal, connecting its components and facilitating electricity flow between the terminated wire and the battery stud or busbar/fuse block/breaker terminal bolt. For optimal performance, you should choose a ring terminal with a highly conductive metal conductor.
All our ring terminal connectors are made of high-purity copper, ensuring maximum current flow to your wired circuits. This material also handles heat spikes without immediate overheating and efficiently dissipates heat if overheating ever happens.
Moreover, the conductor's surface features a thin layer of tin plating to prevent oxidation and corrosion of the underlying copper. This allows reliable performance in humid, salty or acidic environments without degradation. The tin plating also protects the copper conductor from wear, enhancing the durability and longevity of the O-ring connector.
Metric Ring Sizes That Fit Australian Studs and Bolts
When selecting ring terminals for your wiring project, you must consider the size of the terminal studs or bolts on your battery, busbar, fuse block or circuit breaker. These are typically designed using either the US customary system or the International System (IS) metric, which have different nominal diameters, so you must be keen during your selection.
Our ring terminals are based on the IS metric, widely adopted globally and standard in Australia. Hence, you can shop with confidence, as we guarantee they will fit on your battery studs or busbar/fuse block/breaker terminal bolts. Some examples are:
- Blue M5 heat shrink ring terminal: features an "M5" ring connection end, compatible with 5mm studs/bolts.
- Red M5 heat shrink ring terminal: features an "M5" ring connection end, compatible with 5mm studs/bolts.
- Yellow M6 heat shrink ring terminal: features an "M6" ring connection end, compatible with 6mm studs/bolts.
- Red M6 heat shrink ring terminal: features an "M6" ring connection end, compatible with 6mm studs/bolts.
- Yellow M8 heat shrink ring terminal: features an "M8" ring connection end, compatible with 8mm studs/bolts.
- Red M10 heat shrink ring terminal: features an "M10" ring connection end, compatible with 10mm studs/bolts.
- Yellow M10 heat shrink ring terminal: features an "M10" ring connection end, compatible with 10mm studs/bolts.
- Blue M10 heat shrink ring terminal: features an "M10" ring connection end, compatible with 10mm studs/bolts.
Compatibility with a Range of Wire Gauges
Another critical factor when choosing ring terminals for your off-grid vehicle wiring project is compatibility with the wires you intend to terminate. This means ensuring the inner diameter of the hollow barrel end securely grips the wire after crimping or soldering.
Our ring terminals are versatile, as they accommodate a range of wire gauges, including 12β10 AWG, 12β16 AWG, or 16β14 AWG. This reduces the need for multiple connector types, simplifying installation and improving repairability. By covering various wire gauges, our ring terminals also lower purchasing costs, as they are sold in packs of 50 or 100, suitable for multiple projects.
Adequate Clearance Around Terminal Studs and Bolts
When selecting ring terminals, ensure they provide sufficient clearance around terminal studs or bolts. The outer diameter of the connection end ring must not interfere with nearby terminals or components, as this could cause electrical issues like short circuits or arcing.
For example, the Blue Heat Shrink M5 Ring Terminal Connector has a ring connection end with an outer diameter of 7.6mm, requiring approximately 9.6mm of clearance around the terminal stud/bolt to prevent contact with nearby terminals or arcing.
The chart below details the outer diameter and total length of the ring terminal connectors listed above, to help you make a more informed decision for your purchase.
| Ring Terminal | Compatible Wire Gauge | Ring Outer Diameter vs Total Length |
|---|---|---|
| Blue heat shrink M5 | 16β14 AWG (1.25β2.5mmΒ²) | 7.6mm / 30mm |
| Red heat shrink M5 | 22β16 AWG (0.5β1.5mmΒ²) | 8mm / 30mm |
| Yellow heat shrink M6 | 12β10 AWG (4.0β6.0mmΒ²) | 11.3mm / 33.5mm |
| Red heat shrink M6 | 22β16 AWG (0.5β1.5mmΒ²) | 11mm / 34mm |
| Yellow heat shrink M8 | 12β10 AWG (4.0β6.0mmΒ²) | 15mm / 40.5mm |
| Red heat shrink M10 | 22β16 AWG (0.5β1.5mmΒ²) | 13.5mm / 39mm |
| Yellow heat shrink M10 | 12β10 AWG (4.0β6.0mmΒ²) | 14.8mm / 41mm |
| Blue heat shrink M10 | 16β14 AWG (1.25β2.5mmΒ²) | 13.6mm / 39.5mm |
As shown in the chart, multiple ring terminals can support the same stud/bolt sizes but have varying outer diameters and total lengths. Therefore, always ensure the connector you choose fits your mounting space with adequate clearance.
Heat Shrink Insulation for Safe Indoor and Outdoor Wiring
Insulation is another critical factor when selecting ring terminal connectors. As previously noted, it prevents accidental contact with other wires, metal surfaces or your skin, reducing the risk of electrical issues.
All our ring terminals feature heat-shrink tubing insulation, which provides a protective layer to prevent short circuits and shocks. The tubing encases the barrel end, sealing the wire connection against harsh elements like moisture, rain and dirt that can cause corrosion.
Moreover, the heat-shrink insulation adds mechanical strength to the terminated area, reducing stress on the wire from bending, pulling or vibrations during travel on rough terrain. This helps prevent wire fatigue and ensures a durable, reliable connection.
Our connectors feature coloured heat-shrink insulation in red, blue and yellow. These colours allow you to mark the polarity of each wire, simplifying identification during maintenance.
How to Read the Markings on Heat Shrink Ring Terminals
Our heat shrink ring terminal connectors are printed with size details for easy identification of compatible studs/bolts and wire gauges. Markings on the heat-shrink insulation indicate the wire gauge (e.g., 12β10 AWG) that fits snugly in the barrel end for secure termination.
On the other hand, the engravings on the ring connection end specify the stud/bolt size and the cross-sectional area (CSA) in square millimetres (mmΒ²) of the thickest wire you can terminate.
Should You Crimp or Solder Your Ring Terminal Connection?
When shopping for ring terminal connectors, note that construction materials, sizing and craftsmanship vary, with some products outperforming others. Campervan Builders brings you only the best products, which we have personally tested and used in our camper to ensure they perform as described.
After receiving your ring terminals, you can terminate them using the method best suited to your needs. Our ring terminals can be soldered for a highly conductive connection, improving electrical performance. However, crimping produces a more secure mechanical and electrical connection, highly resistant to vibrations when travelling on unsealed roads. After crimping, apply heat to the heat-shrink sleeve to seal the insulation, enhancing environmental protection and stress relief.
Ring Terminals FAQ
What size ring terminal do I need?
Match the "M" size to your stud or bolt diameter: M5 terminals fit 5mm studs/bolts, M6 fit 6mm, M8 fit 8mm and M10 fit 10mm. Then check the wire gauge marking on the insulation to ensure the barrel end grips your wire securely, and confirm the ring's outer diameter leaves enough clearance around nearby terminals.
What are ring terminals made of?
Quality ring terminals use a high-purity copper conductor for maximum current flow, finished with a thin tin plating that prevents oxidation and corrosion in humid, salty or acidic environments and protects the copper from wear.
Is it better to crimp or solder a ring terminal?
Soldering delivers a highly conductive connection, while crimping produces a more secure mechanical and electrical connection that resists vibration on unsealed roads. After crimping, apply heat to the heat-shrink sleeve to seal the insulation against the elements.
Why do ring terminals come in different colours?
The red, blue and yellow heat-shrink insulation lets you mark the polarity of each wire for easy identification during maintenance, and each colour corresponds to a compatible wire gauge range printed on the sleeve.
Ready to wire your camper safely? Browse the full range of heat shrink ring terminals at Campervan Builders, available in packs sized for every 12V project.
