GS3
Electrical
- Feb 3, 2007
- 16
Local (not really important where) electric code has introduced some changes for residential installations for which I would like to hear your opinions. We're talking 220V supplied between neutral and live (one phase of 3 phase system). We are talking about general residential low power circuits equivalent to AWG 12~14.
(1) Code used to allow circuit breakers only breaking the live wire, now double breakers which will break both live an neutral are required in every circuit.
I suppose breaking the neutral as well as the live may add a marginal amount of safety but is it really worth it? I suppose one could think of a situation where not breaking the neutral could present some danger but it seems very, very, remote. The breaker panel now holds fewer circuits or becomes twice as large.
What do you think?
(2) Code now requires a general GFIC protecting the entire installation be installed immediately after the general shutoff circuit interrupter. This causes untold grief with nuisance tripping. I suppose there is plenty of "pre-charge" from stray capacitances to earth from wiring and loads so the least ground fault trips the 30 mA GFCI. GFCI trips and everything goes. No light to see your way to the panel, computer loses your work. If you are away for a few days you will come back to find the food in the freezer is lost. I really do not like this system.
Of course, in other people's homes this is their problem. In my home I have certain circuits not GFCI protected.
IMHO the American system of having GFCIs for each circuit at the delivery point greatly diminishes this problem. I suppose instead of having just one GFCI for the whole installation the problem could be alleviated by dividing the load between two or more GFCIs at the panel. Apart from the cost, this compounds the space problem because space-wise you end up with the equivalent of four breakers per circuit (neutral and live, breaker and GFCI).
What say you?
(3) All wiring has to be in conduit, this has not changed. Up until now only solid wire was allowed but now stranded cable is allowed. I suppose this is to make insertion & pulling easier.
While it definitely makes insertion easier, I am not sure I quite like it and this for two reasons. One is that I have seen very old copper solid wire slightly corroded on the surface but still good inside. With stranded cable I am afraid the effect of any surface corrosion can be much more serious as the individual treads can be much more seriously affected by any corrosion and also in my experience, stranded cable tends to corrode faster because capilarity tends to pull in any corrosives. While this is a serious concern in boats and installations in corrosive atmospheres, it should not be a serious concern in residential installations but, still, it just seems to me solid wire is much preferable.
Another, more immediate concern is that solid wire stands up better to screw connections, etc. I find stranded cable needs to be worked much more carefully and there is much room for damage and bad connections if the operator is not careful.
What is your opinion in this matter of solid vs. stranded conductors?
(1) Code used to allow circuit breakers only breaking the live wire, now double breakers which will break both live an neutral are required in every circuit.
I suppose breaking the neutral as well as the live may add a marginal amount of safety but is it really worth it? I suppose one could think of a situation where not breaking the neutral could present some danger but it seems very, very, remote. The breaker panel now holds fewer circuits or becomes twice as large.
What do you think?
(2) Code now requires a general GFIC protecting the entire installation be installed immediately after the general shutoff circuit interrupter. This causes untold grief with nuisance tripping. I suppose there is plenty of "pre-charge" from stray capacitances to earth from wiring and loads so the least ground fault trips the 30 mA GFCI. GFCI trips and everything goes. No light to see your way to the panel, computer loses your work. If you are away for a few days you will come back to find the food in the freezer is lost. I really do not like this system.
Of course, in other people's homes this is their problem. In my home I have certain circuits not GFCI protected.
IMHO the American system of having GFCIs for each circuit at the delivery point greatly diminishes this problem. I suppose instead of having just one GFCI for the whole installation the problem could be alleviated by dividing the load between two or more GFCIs at the panel. Apart from the cost, this compounds the space problem because space-wise you end up with the equivalent of four breakers per circuit (neutral and live, breaker and GFCI).
What say you?
(3) All wiring has to be in conduit, this has not changed. Up until now only solid wire was allowed but now stranded cable is allowed. I suppose this is to make insertion & pulling easier.
While it definitely makes insertion easier, I am not sure I quite like it and this for two reasons. One is that I have seen very old copper solid wire slightly corroded on the surface but still good inside. With stranded cable I am afraid the effect of any surface corrosion can be much more serious as the individual treads can be much more seriously affected by any corrosion and also in my experience, stranded cable tends to corrode faster because capilarity tends to pull in any corrosives. While this is a serious concern in boats and installations in corrosive atmospheres, it should not be a serious concern in residential installations but, still, it just seems to me solid wire is much preferable.
Another, more immediate concern is that solid wire stands up better to screw connections, etc. I find stranded cable needs to be worked much more carefully and there is much room for damage and bad connections if the operator is not careful.
What is your opinion in this matter of solid vs. stranded conductors?
