electricial shock possible?

[W1QJ]

 indeed. According to the NEC a radio transmitting antenna needs to be made of #14 Cu but #32 will easily handle 1500w. Also, according to the NEC a 240v circuit needs to have 4 wires, 2 of which carry zero current.

The reason for the NEC is for saftey, and not always makes logical sense to hams. The #14 wire requirement has nothing to do with the current handling capability but rather has to do with the strength of the wire instead. So in light of that it does make "some sense". As far as 240v branch circuits, the code DOES NOT say anywhere that they must have 4 wires, that is simply false! The only time the code requires 4 wires is in a 240/120 v circuit. This is a combination circuit where a device will be using both 240v and 120v. Clothes dryers, electric ranges, and most modern type equipment now (unlike years ago) use both voltages. The 4 wires consist of 2 current carrying conductors, phase A and phase B a neutral, and a ground (bond). In such circuit only one wire does not carry current and that is the bond. The other wires indeed carry current, so 2 wires NOT carrying current is false. A "true" 240v branch circuit only requires 3 wires NOT 4. In this case the 3 wires are phase A and phase B and a ground (bond). A neutral is NOT required in a "true" 240v branch circuit. As far as having open wire feeders grounded at the entry point, I doubt the NEC requires open wire feeders to be grounded in this case, however, I will consult my NEC book and check the wording , it may specifically call out coaxial type feed lines. If indeed it does require grounding, that would be wrong and therefore ANYONE is allowed to petition the NFPA for a change in the code.

[AG6K]

The reason for the NEC is for saftey, and not always makes logical sense to hams. The #14 wire requirement has nothing to do with the current handling capability but rather has to do with the strength of the wire instead. So in light of that it does make "some sense"

.

 There's a danger from #32 wire falling on someone? . . . If strength is the issue then phosphor-bronze antenna wire should be specified.

As far as 240v branch circuits, the code DOES NOT say anywhere that they must have 4 wires, that is simply false! The only time the code requires 4 wires is in a 240/120 v circuit. This is a combination circuit where a device will be using both 240v and 120v. Clothes dryers, electric ranges, and most modern type equipment now (unlike years ago) use both voltages.

 So it's unsafe to have 0.33A for a 40W, 120V lamp flowing in the #8-gauge N. wire for an electric range?

The 4 wires consist of 2 current carrying conductors, phase A and phase B a neutral, and a ground (bond). In such circuit only one wire does not carry current and that is the bond. The other wires indeed carry current, so 2 wires NOT carrying current is false.

 There's zero current in two of the four wires when the door is closed and the light is off.

A "true" 240v branch circuit only requires 3 wires NOT 4. In this case the 3 wires are phase A and phase B and a ground (bond). A neutral is NOT required in a "true" 240v branch circuit. As far as having open wire feeders grounded at the entry point, I doubt the NEC requires open wire feeders to be grounded in this case, however, I will consult my NEC book and check the wording , it may specifically call out coaxial type feed lines. If indeed it does require grounding, that would be wrong and therefore ANYONE is allowed to petition the NFPA for a change in the code.

 The NEC requirement is that the antenna feedline shield must be grounded at the entry point to the dwelling. Only people who understand radio should make NEC rules about radio antennas.

 Petitioning a large bureaucracy is a waste of time. When I go to the hardware store I buy 3-conductor 240v plugs/sockets and unshielded 300-ohm TV twinlead.

[AG6K]

Being used to 3-phase, it took me a while to figure out why you said zero current, but, you are correct. Another fine example of regulations just going too far.

 Chortle. . . When the electric dryer door is open there is a small current flowing in the N wire, What's unsafe about 0.33A flowing in #8 Cu?. . . . I'm currently embroiled in a head-butt with SoCal Edison and County Building and Safety over my portable,2500W grid-tie photo-voltaic system. Since there is no South-facing roof on this house I built a portable PV structure that plugs into a 240v, 15A 3-wire outlet with a 100-foot #10 extension cord. I've been pumping surplus electric energy back into the grid for >2-years and I'm still trying to get permits. Meanwhile Edison found out my electric meter was running backwards on sunny days - so they tried to replace my standard bi-directional electric meter with a unidirectional meter -- but I refused because it would not give me 100% credit for the electricity I put back into the grid. . . . My last electric bill was $1.74. My next door neighbor's was $259.

[AG6K]

The reason for the NEC is for saftey, and not always makes logical sense to hams. The #14 wire requirement has nothing to do with the current handling capability but rather has to do with the strength of the wire instead. So in light of that it does make "some sense". ... ....

 The NEC also applies to receiving antennas. Having a transmitting antenna drop to the ground could possibly start a fire, but a receiving antenna?

[N3JBH]

The code in regard to ground & neutral hasn't changed. Normally, neutral may carry current. Normally, ground shouldn't.

Oh i thought he meant that all the coax entries had to come in that way. That was what had me confused.

[K8MHZ]

 Somebody needs to explain to the schlubbs who wrote the NEC that open-wire feedline does not have a shield.

If you took the time to actually read the NEC you would see that shield grounding is an alternative to having antenna discharge units. The NEC requirement for non-shielded antenna lines is a discharge unit. The discharge unit is grounded, not the lines it is protecting.

[K8MHZ]

 The NEC also applies to receiving antennas. Having a transmitting antenna drop to the ground could possibly start a fire, but a receiving antenna?

They still are electrical paths leading to the inside of a building.

[N2RJ]

 The NEC also applies to receiving antennas.

Hey nice apple logo.

[WA7PRC]

If you took the time to actually read the NEC you would see that shield grounding is an alternative to having antenna discharge units. The NEC requirement for non-shielded antenna lines is a discharge unit. The discharge unit is grounded, not the lines it is protecting.

Thanks, Mark. I took that tip from Tom/W8JI. In preparation for putting up my TX-472 tower, I now have my feedlines and ground system up to code:



The wimpy RG-58 cables will go away after the tower is up. The lead to the ground rod is 2" wide copper, appearing at the bottom edge of the plate. Only the fittings in the top are not from DX Engineering.

[K8MHZ]

Thanks, Mark. I took that tip from Tom/W8JI. In preparation for putting up my TX-472 tower, I now have my feedlines and ground system up to code:



The lead to the ground rod is 2" wide copper, appearing at the bottom edge of the plate. The wimpy RG-58 cables will go away after the tower is up.

Very nice! But the CU strap is actually not *exactly* up to code. The NEC requires wire conductors. Of course, they are completely wrong. Your set up is great, but violates the minimum grounding conductor size requirements of the NEC.

"The protective grounding conductor shall be as large as the lead in but not smaller than 10 AWG copper, bronze or copper-clad steel"

The bonding jumper requirements make more sense:

"A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected....."

NEC 810 needs some changes to reflect the use of flat copper strap for antenna protection. "or equivalent" covers it, but without that term, it could be interpreted that only wire is to be used.

On a forum for electricians, one thread is about an inspector making a ham not use 2 inch strap as advised by Polyphaser and instead use 2/0 stranded copper. Of course, the inspector is wrong on so many levels. I made it clear that if an electrical inspector tried that with me there would be fur flying. (I am a Michigan State licensed journeyman electrician)

The NEC is a MINIMUM standard. Methods shown to be safer than the NEC requirements are allowed, but many inspectors are not aware of that.

Again, nice set up!