SC-B5T18-15A
Product overview
BS 546:2025 Tables 16, 17 and 18 gauges for non-interference of switch and plug, 15 A, set of two discs, model SC-B5T18-15A. They check the two “non-interference” requirements: no projection on the engagement face shall prevent a plug from being fully inserted, and the switch actuator, in any of its possible positions, shall not enter the insertion circle of Table 18.
Standard: BS 546:2025 Tables 16 and 17 (flatness and projections on the engagement face) and Table 18 (radius of the insertion circle). For 15 A socket-outlets Table 18 gives 29.46 mm with a switch and 32.26 mm without a switch. The gauges are discs of that radius with three clearance holes for the plug pins; the two discs in this batch are stamped R29.48 and R32.28.
Test procedure: place the appropriate disc on the engagement face with its three holes over the contact tubes and rotate it slowly once around the socket centre. Nothing within the disc area may lift the gauge – switch actuators, cover plates and fixing screws must all stay outside the insertion circle. Use the R29.48 disc for socket-outlets with a switch (checking the actuator in every possible position) and the R32.28 disc for those without a switch.
Construction
- Set of two discs: R29.48 (socket-outlet with switch) and R32.28 (socket-outlet without switch)
- Three pin clearance holes per disc, at the 15 A plug pin positions
- Precision-turned rim, radius tolerance to Table 18, edges deburred
- Disc stamp: BS 546:2025 表18 15A plus radius value and serial number
- Measured radius data and calibration certificate supplied with the goods
Technical parameters
| Model | SC-B5T18-15A |
| Standard | BS 546:2025 Tables 16, 17 and 18 |
| Rating | 15 A |
| Set content | 2 discs |
| Disc 1 radius | R29.48 mm (socket-outlet with switch; Table 18 value 29.46 mm) |
| Disc 2 radius | R32.28 mm (socket-outlet without switch; Table 18 value 32.26 mm) |
| Pin clearance holes | 3 holes, at the 15 A pin positions (earth + 2 current-carrying) |
| Material | Stainless steel, turned and hardened, HRC 50 min. |
| Disc stamp | BS 546:2025 表18 15A + radius + serial number |
BS 546:2025 Table 18 – radius of the insertion circle (15 A)
| Socket-outlet type | Insertion circle radius | Gauge | What it verifies |
| 15 A with switch | 29.46 mm | R29.48 disc | Switch actuator, in any position, shall not enter the insertion circle |
| 15 A without switch | 32.26 mm | R32.28 disc | No projection on the engagement face shall prevent full insertion |
Product pictures
Standard drawing
No Table 18 drawing is provided with this batch. Table 18 is a dimensional table; the discs are manufactured to the tabulated radii and the stamped values R29.48 / R32.28 are the as-built radii. Measured radius data is supplied with the goods.
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