Hi Lyledunn,

Are you suggesting that the presence of a type 1 SPD would mean that it were safe to install OV category I equipment e.g. electronics without further protection? If so... I think that this is misreading the tables: Table 443.2 is a specification for the withstand capability of the various equipment types, which drives where equipment can be installed, whereas Up is the residual voltage after the nominal discharge. So they're not compatible for comparison and e.g. 534 should be used to select an appropriate SPD for sensitive equipment.

However, I think* that if I have the right part that device might in fact be a type 1 + 2 + 3 combined SPD, in which case this (but not the Up directly) would be reasonble grounds for determining that it gives protection to sensitive equipment within the switchboard... The difference between type 1, 2 and 3 is not just the voltage but the design impulse (current) also.

Apologies if I've misinterpreted your question.

*Do check!

Hi Lyledunn,

Are you suggesting that the presence of a type 1 SPD would mean that it were safe to install OV category I equipment e.g. electronics without further protection? If so... I think that this is misreading the tables: Table 443.2 is a specification for the withstand capability of the various equipment types, which drives where equipment can be installed, whereas Up is the residual voltage after the nominal discharge. So they're not compatible for comparison and e.g. 534 should be used to select an appropriate SPD for sensitive equipment.

However, I think* that if I have the right part that device might in fact be a type 1 + 2 + 3 combined SPD, in which case this (but not the Up directly) would be reasonble grounds for determining that it gives protection to sensitive equipment within the switchboard... The difference between type 1, 2 and 3 is not just the voltage but the design impulse (current) also.

Apologies if I've misinterpreted your question.

*Do check!