Bharat Sanchar Nigam Limited - Chennai Telephones - BSNL

Name of Work: Replacement of Class B & B+ C Surge Protection Devices in First Floor at
TE MM Nagar.
Technical Specifications of Surge Protection Devices (SPDs) for 415V AC 50
Hz Power Supply
Applicable Standards
IEC 62305 : Protection against Lightning
Part 1: Basic Principles
Part 2: Risk Assessment
Part 3: Protection of structures
Part 4: Electrical & Electronic equipments within structures
Note: IEC 61024 & IEC 61312 are old standards and are replaced by IEC 62305.
IEC 61643-1: - Surge Protective Devices Connected to Low-Voltage Power Systems:
Performance requirements and testing methods.
IEC 61643-12: - Surge Protective Devices Connected to Low-Voltage Power
Systems:
Selection and application principles
Type of Network – 415V AC 3 phase, 4 wire.
Mains Incoming Panel
Protection at the main incomer of the power supply system – i.e. at the Main Distribution Board
(after the incoming breaker)
Class B/Class I (according to IEC 61643)
3 numbers of lightning arrester for the connection between Phase and Neutral and
one number of lightning arrester between Neutral and Earth with the following
ratings:
Sl.
Specifications
Parameters
No
Line to Neutral Neutral to Earth
1. Type Encapsulated/Non-exhausting Spark
Gap
2. Nominal Voltage, Un 230V, 50/60 Hz
3. Maximum Continuous operating ≥ 255 V
255 V
Voltage Uc
4. Lightning Impulse Current 50 kA (10/350
sec)
≥ 100 kA(10/350
sec)
5. Voltage Protection Level, Up < 1.3 KV
6. Response Time < 100 nano seconds
7. Operating temperature range -40C to +85C
8. Mounting on DIN Rail
9. Degree of Protection IP 20
10. Max. Back-up fuse 500 A gL/gG NA
11. Local Indication LED Indication NA
Contractor Internet Downloaded copy Executive Engineer (E)
Page No. 39 of 40