Self impedance..... My new power words when I explain to my colleagues who keep doing this. Some have argued with me, saying by keeping the grounds separated another sparky well know there's two different circuits in the junction box!! Oh Boy.
Respect to 250.148(A): don't see a major inconvenience to the fact that for a few milliseconds the EGC of the other circuit is the one who conducts the fault current. While I understand your point and have no problem with the requirement (which is easy to meet), I can't imagine a time or case where this represents a real safety issue. In the event that both are connected, ideally being of the same or similar distance, the current would be distributed in equal magnitude in both and even so we could have hundreds of amperes in the cable that contains the ungrounded conductor that does not present the failure. But, it is personal opinion. Thanks Ryan.
5:00 I would think that combining all EGCs would not be ideal if there are circuits on different breakers. My thought is it would mess with the GFCI/AFCI with the parallel EGC paths and lower the current below what would normally be detected.
I see plenty of IG circuits in large scale Sound and Video system installs. They can still be useful...but are not without drawbacks. What other applications were they used in...back in the day? And, as always: Thank you so much for the insight!!!
Back in the day I worked on a lot of instrumentation circuits (1-5 vts/4-20 ma ) where the ground wire and shield were only terminated on one end. This was to prevent “ground loop” voltages/ currents. I never really understood this???
When you get to 334.40(b) are you going to talk about why Tyco romex splice kits are seemingly allowed in a broader range of situations than in previous code cycles? Super curious about this one
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This is really excellent! I really appreciate the explanations of "why." Just great!
Look forward to seeing you speak in Bay City at the IAEI meeting!
I'm looking forward to it too. Be sure to say hello!
You helped me pass my Jman and masters test, thank you for all the videos!
Could u elaborate on 404.9 b I didn't really see anything un ordinary?
Self impedance..... My new power words when I explain to my colleagues who keep doing this. Some have argued with me, saying by keeping the grounds separated another sparky well know there's two different circuits in the junction box!! Oh Boy.
Respect to 250.148(A): don't see a major inconvenience to the fact that for a few milliseconds the EGC of the other circuit is the one who conducts the fault current. While I understand your point and have no problem with the requirement (which is easy to meet), I can't imagine a time or case where this represents a real safety issue.
In the event that both are connected, ideally being of the same or similar distance, the current would be distributed in equal magnitude in both and even so we could have hundreds of amperes in the cable that contains the ungrounded conductor that does not present the failure.
But, it is personal opinion. Thanks Ryan.
5:00 I would think that combining all EGCs would not be ideal if there are circuits on different breakers. My thought is it would mess with the GFCI/AFCI with the parallel EGC paths and lower the current below what would normally be detected.
GFCI measures between hot and neutral, ground is not involved.
What’s ironic is that twisted ground might be more solid than a crimp or even a wire nut.
How do you figure?
@@R900DZ The twisted together wires seem quite solid if you do them right.
@@suspicionofdeceit seem? And what do mean by “solid?”
I see plenty of IG circuits in large scale Sound and Video system installs. They can still be useful...but are not without drawbacks.
What other applications were they used in...back in the day?
And, as always: Thank you so much for the insight!!!
Hospitals
Computers and electrical measuring equipment
Back in the day I worked on a lot of instrumentation circuits (1-5 vts/4-20 ma ) where the ground wire and shield were only terminated on one end. This was to prevent “ground loop” voltages/ currents. I never really understood this???
When you get to 334.40(b) are you going to talk about why Tyco romex splice kits are seemingly allowed in a broader range of situations than in previous code cycles? Super curious about this one
I shall.
I can't find those anywhere in my area.