1. Product Overview
The Grothe Bell Transformer GT 50810 (Model: 1512020) is a reliable and fail-safe bell transformer designed for various applications, primarily for powering doorbells and similar low-voltage systems. It converts standard mains voltage (230 V AC) to a lower, safe voltage (8 V AC) suitable for bell systems.
Key features include:
- Transformer fail-safe design for enhanced safety.
- Primary Voltage: 230 V.
- Secondary Voltage: 8 V AC.
- Secondary Current: 1 A.
- Maximum Output Power: 8 W.
- Suitable for surface mounting and modular versions.
- Short-circuit protection.

Figure 1: Front view of the Grothe Bell Transformer GT 50810, displaying its primary and secondary voltage specifications and connection points.
2. Safety Information
WARNING: Electrical shock hazard. Installation and maintenance should only be performed by a qualified electrician in accordance with all local and national electrical codes.
- Always disconnect power at the main circuit breaker before installing or servicing the transformer.
- Ensure proper wiring and insulation to prevent short circuits.
- Do not exceed the specified maximum output current (1 A) or power (8 W).
- The transformer is designed for indoor use only. Avoid exposure to moisture or extreme temperatures.
- Verify that the primary voltage (230 V AC) matches your mains supply.
- This device features short-circuit protection, but proper installation is still crucial.
3. Setup and Installation
The Grothe Bell Transformer GT 50810 is suitable for surface mounting and integration into modular systems. Follow these general installation guidelines:
- Power Disconnection: Before beginning any work, ensure the main power supply to the installation area is completely disconnected at the circuit breaker.
- Mounting:
- Choose a suitable, dry location for mounting, away from direct heat sources or moisture.
- Securely mount the transformer using appropriate screws or clips for surface mounting, or integrate it into a compatible modular enclosure.
- Wiring - Primary Side (Input):
- Connect the 230 V AC mains supply to the primary terminals (marked PRI: ~230-240V 50Hz). Refer to the wiring diagram on the transformer casing.
- Ensure correct polarity and secure connections.
- Wiring - Secondary Side (Output):
- Connect your bell or low-voltage device to the secondary terminals (marked SEC: ~8V / 1.0A).
- Verify that the connected device's voltage and current requirements do not exceed the transformer's output (8 V AC, 1 A).
- Verification: Double-check all connections for tightness and correctness.
- Power Restoration: Once all connections are secure and verified, restore power at the main circuit breaker.

Figure 2: Rear view of the transformer, illustrating its mounting mechanism and "Made in Germany" marking.
4. Operating Instructions
Once properly installed and connected, the Grothe Bell Transformer operates continuously to provide the necessary low voltage for your bell system. There are no user-adjustable settings or controls on the transformer itself.
- The transformer will supply 8 V AC power to the connected load as long as the primary 230 V AC input is present.
- Its fail-safe design and short-circuit protection ensure reliable operation and safety under normal conditions.
5. Maintenance
The Grothe Bell Transformer is designed for maintenance-free operation. However, periodic checks are recommended:
- Visual Inspection: Periodically inspect the transformer and its connections for any signs of damage, loose wires, or overheating (discoloration).
- Cleaning: If necessary, gently wipe the exterior of the transformer with a dry, soft cloth. Do not use liquid cleaners or solvents.
- Professional Check: If you suspect any malfunction or damage, consult a qualified electrician for inspection and repair. Do not attempt to open or repair the transformer yourself.
6. Troubleshooting
If your bell system is not functioning correctly, consider the following troubleshooting steps:
| Problem | Possible Cause | Solution |
|---|---|---|
| No power to bell/device |
|
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| Bell/device not working correctly (e.g., weak sound) |
|
|
| Transformer is hot to the touch |
|
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7. Specifications
Detailed technical specifications for the Grothe Bell Transformer GT 50810:
| Attribute | Value |
|---|---|
| Brand | Grothe |
| Model Number | 1512020 |
| Part Number | 1512020 |
| Primary Voltage | 230 V AC |
| Secondary Voltage | 8 V AC |
| Secondary Current | 1 A |
| Maximum Output Power | 8 W |
| Minimum Frequency | 50 Hz |
| Maximum Frequency | 50 Hz |
| Product Dimensions (L x W x H) | 9.4 x 7.19 x 3.99 cm |
| Item Weight | 235 g |
| Mounting Type | Surface Mount |
| Short Circuit Protection | Yes |
| Specification Met | CE, UL |
| Global Trade Identification Number (GTIN) | 04011459142070 |

Figure 3: Dimensions of the Grothe Bell Transformer.
8. Warranty and Support
For warranty information and technical support, please refer to the official Grothe website or contact your local distributor. Keep your purchase receipt as proof of purchase.
For further assistance, you may contact Grothe customer service or the retailer from whom you purchased the product.





