>
>
>R.Measures wrote:
>>
>
>>
>> ** The neutral in the 240V outlet for the amplifier is shared with every
>> 120V and every 240V circuit in the house because All of the neutrals
>> connect to the neutral/ground terminal strip in the breaker-box. If I am
>> fortunate, it is that I know Ohm's law good enough to get by.
>>
>> __ Which is what I do on the 240v outlet for the tetrodes-with-handles
>> mains outlet. // The imbalance current is c. 85mA-avg in the
>> neutral/ground because I utilize one side of the mains-neutral potential
>> to power a half-wave rectified, C-filtered 160VDC supply for operating
>> the high-speed T/R relays. Although there are some who would be alarmed
>> about the potential-drop in 99' of #6 wire at 85mA, I am not one of them.
>>
>>
>
>Rich, I am sure that you know and understand this stuff but some others
>may not.
>
>1. The biggest reason for having separate ground and neutral wires is to
>insure safety in case the neutral should open (in the case of a common
>ground/neutral system like you use.
>Even your 85 ma that you are running on your common ground/neutral line
>can be a hazard. If the ground/neutral line opens anywhere you will have
>120 volts at chassis through the transformer primary with enough current
>to cause electrocution if you are between chassis and some other ground.
>
** Providing this person was standing in water.
>In your system it may not be too likely to happen. However in many
>wiring installations it can easily happen.
>
>One house that I owned years ago (was a brand new house too) had
>problems with some of the wiring. Upon further looking I found that just
>about every outlet in the house had the wires wrapped around the screw
>terminals loosely as you normally would, but the screws were never
>turned down! Most of the outlets worked properly as far as I knew. I
>would have never known if I had not opened them up and looked at them.
>That is unless I had a fire first!
>Suppose in that house I had a 220 outlet with only 3 wires used as you
>do above. I could have very easily had a poor (guaranteed to be poor!)
>neutral/ground lead.
>
>If your 220 line had it's ground/neutral connection wired like that and
>you were using it as a neutral/ground you could very easily have a "hot
>chassis". I have also seen "electrician" installations where the lugs in
> the breaker panel where not tightened. Wires slipped into hole but
>never tightened down. they make a connection but not a reliable one.
>
>It is easy to have a poor outlet connection too. Fingers in the plug not
>making proper contact. Especially on older / well used outlets.
>
>If any of these things happen on your neutral/ground line then you are
>sure to have a "hot" chassis because you are asking that line to carry
>current that is tied to the chassis.
>
>But if you have a separate neutral and ground line then even if you
>would have a poor connection on ANY of the lines (even the ground line)
>you would not have a "hot" chassis. Unless of course there were multiple
>faults.
** If the screws are not tightened on the ground and neutral wires, you
would.
>
>2. As to "proper to code installation of wires" you may use any color
>wire that you wish. Even all black wires. Yes even for ground and
>neutral! But each end is supposed to be tagged with proper colored tape
>to identify them.
** I identify them by size. #6 is ground/neutral and the #4s are mains.
>I do it in my own stuff mainly to be able to identify what I did several
>years latter.
>If you use 3 conductor Romex for a 220 line (black, white and bare)
>the white wire should be marked with red tape on each end. The main
>reason to do so is to tell someone that may be in that circuit doing
>repair work that that is a 220 line and not a 120 volt line neutral.
>
>3. A three wire 220 line as above is perfectly fine with the NEC as
>long as it is used as "hot, hot' ground and no neutral is involved.
** How can neutral be not involved if the not-hot third wire connects to
the ground/neutral terminal strip?
>
>A 3 wire 220 line is fine for most of the amplifiers provided there is
>no 120 volt / neutral requirement.
** I have been using one half of the amplifier's 240vct, 20A circuit to
power my 120v radio and soldering iron for the past 28-years.
>
>4. I saw someone post earlier that "ground wires and neutral wires were
>intermingled on the lugs in the breaker panel". Even though the two buss
>bars are tied together in the panel the proper way (to NEC code) is to
>connect all the neutral wires to the neutral buss bar and all the ground
>wires to the ground buss bar and not intermingle them.
** In my General Electric Co. box there is one common strip for all of
the neutral and ground wires
>There is good reason for it.
** Apparently, GE did not think so.
>Though they may be electrically the same,
>it is much easier to identify which is which when looking in the crowded
>panel to try and identify a wire. Also if you have an external main
>breaker or this panel happens to be a sub panel the ground and neutral
>would NOT be the same at that point.
>
>5. Yes inspectors do (should) look for properly identified (proper
>color) wires. You may know what they are on your own work but the next
>guy that comes along may not know where they are supposed to go unless
>they are the standard color codes.
>
** I trust my DMM more than I trust a color.
cheers, Gary
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