Neutral Questions

[Zzzap]

Lately I have been wondering about neutrals and their
properties. I know for fact that getting hit by a 277 neutral is
painful as hell. Some have told me that neutrals hurt more than
hot wires because you aren't expecting it. I beg to differ.

I even have tried to use my voltage "ticker," as it's known in
the field, based on the hall effect, to see what neutral had a
load. I never have gotten a reading even when there is a load.
Can someone give me a decent explanation as to the reason? Is
there any suitable way of testing to see if a neutral is
carrying a load besides an amprobe? My guess to the reason why
you can't get a reading using the "ticker" is because the
neutral hasn't any inductance, or very little.
What happens to the inductance from the hot through the resistor
(device) to the neutral? How much voltage is in the neutral on a
120v system? I've always associated inductance with voltage.
What I know of the properties of the neutral it would indicate
that my association has some flaws in it.

I'll leave my other questions on the neutral for another thread,
and other questions. This one is long winded enough.

TIA.

 

[[email protected]]

Lately I have been wondering about neutrals and their
properties. I know for fact that getting hit by a 277 neutral is
painful as hell. Some have told me that neutrals hurt more than
hot wires because you aren't expecting it. I beg to differ.

I even have tried to use my voltage "ticker," as it's known in
the field, based on the hall effect, to see what neutral had a
load. I never have gotten a reading even when there is a load.

Well, the terminology you use is a bit off. In this case,
I don't think it hinders understanding - but some day it
will, for sure. Neutrals don't have a load, per se, the way
you seem to mean it. The neutral is not allowed to be
switched, so with hardwired lights and appliances, the
neutral is always connected to a load.

I think what you are really talking about is whether or
not current is flowing on the neutral, not whether or not
the neutral "has a load".

Can someone give me a decent explanation as to the reason? Is
there any suitable way of testing to see if a neutral is
carrying a load besides an amprobe?

Again, I'll translate this to the question "is there current
flowing on the neutral or not?". The safest way to determine
that is to use an amprobe. Perhaps there is a high quality
hall effect ticker available - I don't know - but my
Greenlee ticker sometimes fails to detect while my amprobe
never does. There are other means that involve disconnecting
the neutral, but that can get you "bit".

My guess to the reason why
you can't get a reading using the "ticker" is because the
neutral hasn't any inductance, or very little.

No, that's not the reason. The neutral wire has the same
inductance as the hot and the ground, assuming all three
wires are the same size and length. However, the neutral
is connected to ground, while the hot is not, so that
makes a difference.

What happens to the inductance from the hot through the resistor
(device) to the neutral?

Inductance in that case would be irrelevant - it would
have a negligible affect on the voltage and current in
the circuit.

How much voltage is in the neutral on a
120v system?

If there is no current flowing in the neutral, it
would be at 0 volts with respect to ground, and
120 volts, with respect to hot.

I've always associated inductance with voltage.

That may be ok - but the trouble is that the picture is
incomplete. You need more pieces of the "jig saw puzzle"
to make the picture meaningful.

What I know of the properties of the neutral it would indicate
that my association has some flaws in it.

I'll leave my other questions on the neutral for another thread,
and other questions. This one is long winded enough.

TIA.

I'll take a stab at what might hit the target. 277 volts
is often associated with inductive loads like fluorescent
lights - that may be the association you mention.

Inductive loads can create a voltage "kick" when they are
disconnected. The voltage "kick" can be many times greater
than the supply voltage.

So - when one disconnects a current carrying wire from an
inductive load - such as fluorescent lights - a voltage much
higher than the supply can be generated. If that voltage
goes through you, you'll get a nasty jolt.

 

[Perion]

Lately I have been wondering about neutrals and their
properties. I know for fact that getting hit by a 277 neutral is
painful as hell. Some have told me that neutrals hurt more than
hot wires because you aren't expecting it. I beg to differ.

If the 277 neutral is grounded at the transformer you won't get shocked
unless you break open a connection. If you open up a 277 neutral connection
and touch the wire going to the load, you will effectively be providing a
path from the 277 circuit hot, through the load(s), through your body, to
ground. The shock can be pretty bad - especially if your body resistance is
low (sweating) and the circuit contains lighting ballasts.

I even have tried to use my voltage "ticker," as it's known in
the field, based on the hall effect, to see what neutral had a
load. I never have gotten a reading even when there is a load.
Can someone give me a decent explanation as to the reason?

Tick tracers are capacitive coupled voltage sensors. They work as a
series-connected, capacitive-coupled circuit using your body as the
capacitively coupled path to ground. Notice the fact that they do use ground
as the voltage reference so measuring a grounded neutral conductor won't
produce any measurement ticks..

Perion