S
According to clause 8.9.1.12, a secondary circuit derived from a SUPPLY MAINS will normally be overvoltage category I according to IEC 60664-1 if the MAINS PART is overvoltage category II.
The 8.9.1.12 also says, where a secondary circuit is not earthed and is derived from a SUPPLY MAINS, the circuit shall be subjected to the requirements for primary circuits in Table 13 and Table 14.
However, I don't know if the statement of overvoltage category I also applies when checking the values from Table 13 and 14.
For example:
- Rated MAINS = 240V, 50-60Hz;
- MAINS overvoltage category II;
- Pollution degree 2;
- The floating secondary circuit powerd from insulation transformer = 120V;
Is the required clearance between such secondary circuit and unearthed enclosure (two MOOP) 4.0 mm @ CAT II or 2.0 mm @ CAT I?
Please advise!
Thank you very much!
The 8.9.1.12 also says, where a secondary circuit is not earthed and is derived from a SUPPLY MAINS, the circuit shall be subjected to the requirements for primary circuits in Table 13 and Table 14.
However, I don't know if the statement of overvoltage category I also applies when checking the values from Table 13 and 14.
For example:
- Rated MAINS = 240V, 50-60Hz;
- MAINS overvoltage category II;
- Pollution degree 2;
- The floating secondary circuit powerd from insulation transformer = 120V;
Is the required clearance between such secondary circuit and unearthed enclosure (two MOOP) 4.0 mm @ CAT II or 2.0 mm @ CAT I?
Please advise!
Thank you very much!
Last edited by a moderator: