Is an R.C.D. really needed on a 55-0-55 Volt supply as used on construction sites?
Z.
In most circumstances, with only 55 volts to earth I would not consider an RCD to be required.
There are two main exceptions, firstly to tick a box if ones employer, or some other authority says "RCDs to be used on all portable power tools" Without any consideration as to supply voltage or other circumstances.
Secondly, I would consider an RCD to be a prudent extra precaution in higher risk conditions such as standing in water, or in the rain. The better choice in such cases is often to use compressed air for power tools and LPG or paraffin for lighting.
55 volts to earth is clearly much less risky than 240 volts, but it is still over twice the limit for SELV, and an RCD could therefore be prudent in high risk situations.
Is an R.C.D. really needed on a 55-0-55 Volt supply as used on construction sites?
Z.
In most circumstances, with only 55 volts to earth I would not consider an RCD to be required.
There are two main exceptions, firstly to tick a box if ones employer, or some other authority says "RCDs to be used on all portable power tools" Without any consideration as to supply voltage or other circumstances.
Secondly, I would consider an RCD to be a prudent extra precaution in higher risk conditions such as standing in water, or in the rain. The better choice in such cases is often to use compressed air for power tools and LPG or paraffin for lighting.
55 volts to earth is clearly much less risky than 240 volts, but it is still over twice the limit for SELV, and an RCD could therefore be prudent in high risk situations.
