Hey Greg,
That really strikes me as strange and don't get me wrong I'm not having a "go" at American electrical practices.
In a country that if something goes wrong, you can have every lawyer in town turn up and apportion blame (this is only my assumption looking in through the window), it seems crazy that something like basic electrical testing is not carried out.
And to be fair, it is not hard to do at all.
We work on this over here and this is an industry-standard testing regime:
- Earth Continuity - This makes sure that there is an Earth Electrode into the ground and what resistance it has.
- Insulation Resistance - This is done with all cables coming into the switchboard, between all conductors and Earth.
- Polarity Test - Make sure that the Main Phase and Neutral conductors are not transposed.
All of the above tests are done with no power supplied to the installation.
When supply is attained, the following tests are carried out:
- Earth Fault Loop Impedance - This is done so that the integrity of the Circuit Protection Devices will disconnect a faulty circuit within 0.4s, this is a test from the most distant socket-outlet in the installation from the switchboard, through the wiring of the Installation, back to the supply transformer and back to the point of test, there are charts that will tell you if this passes or fails based upon the type of circuit protection used, the size of cable used in that circuit.
If the available fault current is too low to operate the fuse or CB on that circuit will not operate causing a potential fire due to heating of the conductors in that cable, setting the insulation on fire. - Operation of RCD's - GFCI's may be different, over here an RCD must trip within 300mS with a maximum trip current of 30mA ( there are different RCD's for medical areas, but that is outside the scope of this).
The worst thing that we strike over here is that the Liney from the PoCo, has hooked up the mains coming into the house or whatever, backwards, they are meant to test this, it is Liney 101, otherwise when the installation is livened, there is either a very loud bang and some flames or all of the exposed metalwork (like faucets (taps) have full mains voltage on them, which is not great if you're looking to have a shower in your new house.
