Re: [Elecraft] 240V Line
I concur. As result of this discussion and because I will soon add another 240vac outlet to serve my 50v-50a switching PS being installed to power a 1100w surplus ch.2 TV Harris amplifier (for use on 6m), I looked closely at some of the twist-lock plugs I had in my parts. They are three contact plugs, so are unable to carry a safety ground for splitting out 120vac. They are legal for 240vac as the third contact is the safety ground. When wiring my shack for 240vac I bought No.8-4 conductor cable (three-No. 8 and one solid copper No.12 wire in the cable. So the 60amp load box is properly connected to provide 120v break out as well as 240vac with standard breakers. But my 240v outlets are only good for 240v as a result. My 4-kV HVPS uses both 240 and 120v and has two separate power cables supplying this (properly oriented neutrals and safety grounds). As Tim says, below, improper wiring can lead to bad operating conditions and UNSAFE operations. If you do not understand any part of what is being said - then you should not do the 240v wiring - hire a reputable, licensed, bonded electrician. Several years ago a local store owner had some wiring done in his house by a friend that knew electrical wiring. The friend connected the 240v service incorrectly cross connecting one of the hot and the neutral which resulted in all the 120v circuits carrying 240v. The store owner lost his furnace blower, microwave, TV, stereo, and most of his lights to the tune of several thousand dollars - but saved on (not) hiring a competent electrician. Fortunately no was harmed and his house did not burn down! 73, Ed - KL7UW -- Date: Mon, 29 Dec 2014 19:12:46 -0700 From: Tim Groat tcgr...@mesanetworks.net To: elecraft elecraft@mailman.qth.net Subject: Re: [Elecraft] 240V Line Message-ID: 54a20a1e.20...@mesanetworks.net Content-Type: text/plain; charset=utf-8; format=flowed What Jim says here is correct. The old exception that allowed returning 120V loads to the bare or green grounding wire of a 240V circuit was very limited, allowed only for a few large appliances (dryers, stoves/ovens, and water heaters IIRC) which would be disconnected only for maintenance or replacement. The exception never applied to ham equipment. There are at least three possible Bad Things that can happen when you use a ground to carry operating current: (1) Some of the 120V load current returns by way of the coax, keying line, ALC line, the rig and its power supply, the antenna grounding system, etc.--anything connected to the amplifier chassis. This current often causes a stubborn hum in your transmitted signal (and other ill effects). (2) If the circuit has GFCI protection, the 120V load current is likely to trip the GFCI. (3) If the ground wire opens for any reason, the 120V load current has nowhere to go except the unintended paths, in particular through you if you are touching anything connected to the amplifier. This danger is the primary reason the NEC no longer allows combining neutral and ground conductors anywhere beyond the power service equipment (master disconnect enclosure). So if you have an older amplifier wired with 120V loads to chassis, it's wise to spend the time and money to make it safer and better by keeping the 120V load currents out of the chassis ground connections. --Tim (KR0u) 73, Ed - KL7UW http://www.kl7uw.com Kits made by KL7UW Dubus Mag business: dubus...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
On Tue,12/30/2014 12:01 AM, Edward R Cole wrote: I concur. As result of this discussion and because I will soon add another 240vac outlet to serve my 50v-50a switching PS being installed to power a 1100w surplus ch.2 TV Harris amplifier (for use on 6m), I looked closely at some of the twist-lock plugs I had in my parts. They are three contact plugs, so are unable to carry a safety ground for splitting out 120vac. WRONG! ALL power outlets MUST include safety ground (the green wire). To do otherwise is both unsafe and a violation of virtually all building codes in the civilized world. A 240V outlet with a 3-circuit plug MUST carry the two 240V phase conductors and GROUND, NOT NEUTRAL. If you want to connect equipment that includes a 120V load to that circuit, you MUST use a 4-circuit plug for that load. In North America, nearly all homes are supplied by a transformer (outside the premises) with a center-tapped 240V secondary. The center tap is the neutral. 240V loads are connected end-to end, 120V loads are connected end to neutral. Those ends are called phases. To connect dedicated 120V loads to that circuit, the 120V outlets must have one of the phase conductors, neutral, and ground. To equalize loading, it's good practice to split those 120V outlets between the two phase conductors (that is, opposing sides of the 240V transformer). They are legal for 240vac as the third contact is the safety ground. Yes. When wiring my shack for 240vac I bought No.8-4 conductor cable (three-No. 8 and one solid copper No.12 wire in the cable. So the 60amp load box is properly connected to provide 120v break out as well as 240vac with standard breakers. But my 240v outlets are only good for 240v as a result. That sounds fine, except that what you can connect to those 240V outlets depends on how they are wired. If they are 3-circuit outlets with phase, phase, and ground, you can, indeed, connect only a 240V load. If they are 4-circuit outlets with phase, phase, neutral, and ground, you can connect a load that draws both 240V between the phases and 120V from one phase to neutral. Also, I'd be concerned about the size of that ground conductor. In general, the ground conductor must be sized at least equal to the phase conductors. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
On 12/30/2014 9:35 AM, Jim Brown wrote: In general, the ground conductor must be sized at least equal to the phase conductors. I was always under the impression that the ground wire must be sized for the circuit overcurrent rating (i.e. breaker/fuse rating). I have on several occasions specified circuit (and neutral) ampacities greater than the overcurrent rating just to eliminate voltage drop at the load. This is important in low-voltage (12/24/48 v) applications in comm centers. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
I'm not an electrician, but I am currently having my house wiring re-done by an electrician and this is my understanding: If you want to run 220V and 110V outlets from the same breaker, you need to use a sub-panel with separate breakers for the 110V circuits. Four wires are needed from the main panel, two hots, neutral and ground. The ground can be a smaller gauge so long as it goes only to circuits that are protected by a circuit breaker suited for that gauge. I did something similar to that when I wired my well, which is about 400 ft away from my house. I wanted a 110V outlet and light in the pump house as well as 220V for the pump. Alan N1AL On 12/30/2014 09:35 AM, Jim Brown wrote: On Tue,12/30/2014 12:01 AM, Edward R Cole wrote: When wiring my shack for 240vac I bought No.8-4 conductor cable (three-No. 8 and one solid copper No.12 wire in the cable. So the 60amp load box is properly connected to provide 120v break out as well as 240vac with standard breakers. But my 240v outlets are only good for 240v as a result. That sounds fine, except that what you can connect to those 240V outlets depends on how they are wired. If they are 3-circuit outlets with phase, phase, and ground, you can, indeed, connect only a 240V load. If they are 4-circuit outlets with phase, phase, neutral, and ground, you can connect a load that draws both 240V between the phases and 120V from one phase to neutral. Also, I'd be concerned about the size of that ground conductor. In general, the ground conductor must be sized at least equal to the phase conductors. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
Folks - Let's close this thread for now to reduce list SNR due to the large volume of posts. In the future, please also refrain from using ALL CAPS and ! in emails, as those are interpreted as shouting and are not appropriate for this list. 73, Eric elecraft.com On 12/30/2014 9:35 AM, Jim Brown wrote: On Tue,12/30/2014 12:01 AM, Edward R Cole wrote: I concur. As result of this discussion and because I will soon add another 240vac outlet to serve my 50v-50a switching PS being installed to power a 1100w surplus ch.2 TV Harris amplifier (for use on 6m), I looked closely at some of the twist-lock plugs I had in my parts. They are three contact plugs, so are unable to carry a safety ground for splitting out 120vac. WRONG! ALL power outlets MUST include safety ground (the green wire). To do otherwise is both unsafe and a violation __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
What Jim says here is correct. The old exception that allowed returning 120V loads to the bare or green grounding wire of a 240V circuit was very limited, allowed only for a few large appliances (dryers, stoves/ovens, and water heaters IIRC) which would be disconnected only for maintenance or replacement. The exception never applied to ham equipment. There are at least three possible Bad Things that can happen when you use a ground to carry operating current: (1) Some of the 120V load current returns by way of the coax, keying line, ALC line, the rig and its power supply, the antenna grounding system, etc.--anything connected to the amplifier chassis. This current often causes a stubborn hum in your transmitted signal (and other ill effects). (2) If the circuit has GFCI protection, the 120V load current is likely to trip the GFCI. (3) If the ground wire opens for any reason, the 120V load current has nowhere to go except the unintended paths, in particular through you if you are touching anything connected to the amplifier. This danger is the primary reason the NEC no longer allows combining neutral and ground conductors anywhere beyond the power service equipment (master disconnect enclosure). So if you have an older amplifier wired with 120V loads to chassis, it's wise to spend the time and money to make it safer and better by keeping the 120V load currents out of the chassis ground connections. --Tim (KR0u) On 12/24/2014 2:50 PM, Jim Brown wrote: You may be confusing a 120/240 outlet that has a four circuit plug (phase, phase, neutral, and Green) and can serve both 120V and 240V loads, with a 240V outlet that has a three circuit plug and serves only 240V loads. There is no neutral in a 240V outlet, and as noted above, it is illegal to connect a 120V load between one phase and the Green wire (Equipment Ground). That 120/240 circuit can feed both 120V and 240V outlets. A neutral IS required to feed those 120V outlets. --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
In retrospect, its better if you contract a licensed electrician to run 240v wiring as his license is at risk and is liable if codes are violated. If you are not sure of the code and regulations, then I would say don't DIY. I am lucky as there is no zoning or covenants where I live. Legally, perhaps a building permit is required (by the county) but standard practise is to ignore it if owner built. I put up a 12x38-foot shed wired with lights and added a backyard driveway with no permits. The property assessor has visited since and added the improvements with nothing said. But this is rural Alaska where things are more relaxed. Also, I worked for a licensed electrician when I was younger so I am familiar with std practise. I hired electrical work at my old workplace so I had a business relationship with electrical contractor who was willing to sign-off on my work (he did the inspection). My prior home was owner-built in 1955 1971 and wired by the owner with 2-wire outlets. FHA bought off on that (grandfathered it) so I did not have to rewire the house (newer half was done with U-ground outlets. I did have to fix a bunch of ground faults and other mistakes and add GFI outlets in kitchen and bathroom. I opened one outlet in the utility room to find black charred wiring (I removed the outlet and used a blank cover and removed the circuit at the breaker box). But current home is built in 1994 and modern five-star energy home - done right. A plus is that utilities are buried so HF line noise is low. Ham radio was a consideration when we chose the home. 73, Ed - KL7UW http://www.kl7uw.com Kits made by KL7UW Dubus Mag business: dubus...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
On 12/24/2014 10:39 AM, Jim Brown wrote: Installing a 240V outlet is not a big deal unless the construction of your home makes it difficult to run the cable. Barring that, a competent electrician should be able to do that in a half day; a difficult run could double the work. All that is required is a pair plus a Green wire. If you also want 120V outlets from the same circuit, you'll need another conductor for the neutral. IIRC the latest code update now requires the separate neutral (white wire) to be run in all 240V circuits. I did that in a 1969 when I finished the basement in a year-old home! 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
On Wed, Dec 24, 2014 at 2:13 PM, Phil Kane k2...@kanafi.org wrote: On 12/24/2014 10:39 AM, Jim Brown wrote: Installing a 240V outlet is not a big deal unless the construction of your home makes it difficult to run the cable. Barring that, a competent electrician should be able to do that in a half day; a difficult run could double the work. All that is required is a pair plus a Green wire. If you also want 120V outlets from the same circuit, you'll need another conductor for the neutral. IIRC the latest code update now requires the separate neutral (white wire) to be run in all 240V circuits. I did that in a 1969 when I finished the basement in a year-old home! Even if that is true,and I suspect all is a mis-statement, that doesn't automatically mean that YOUR Authority Having Jurisdiction has adopted the latest code (or the previous one or the one before that). Things move slowly in some places. 73, geo - n4ua 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to n4ua...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
On Wed,12/24/2014 11:41 AM, Charlie T, K3ICH wrote: A lot of the older amps (Thunderbolt for example) had 120 V fans wired from one hot to ground. I always wondered about that. I think that used to be legal, but it is no longer, and it's very bad practice. The better ones (Ten Tec Titan, for example) run a 120V fan between one side of the power transfomer primary and the center tap. It is now illegal for the Green wire to carry load current. On Wed,12/24/2014 11:13 AM, Phil Kane wrote: IIRC the latest code update now requires the separate neutral (white wire) to be run in all 240V circuits. I did that in a 1969 when I finished the basement in a year-old home! You may be confusing a 120/240 outlet that has a four circuit plug (phase, phase, neutral, and Green) and can serve both 120V and 240V loads, with a 240V outlet that has a three circuit plug and serves only 240V loads. There is no neutral in a 240V outlet, and as noted above, it is illegal to connect a 120V load between one phase and the Green wire (Equipment Ground). That 120/240 circuit can feed both 120V and 240V outlets. A neutral IS required to feed those 120V outlets. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
Electric ranges used to have a 110 VAC outlet in which the ground and neutral were wired together. (The 220V plug had only three prongs.) I always wondered how they got away with that. Alan N1AL On 12/24/2014 01:50 PM, Jim Brown wrote: On Wed,12/24/2014 11:41 AM, Charlie T, K3ICH wrote: A lot of the older amps (Thunderbolt for example) had 120 V fans wired from one hot to ground. I always wondered about that. I think that used to be legal, but it is no longer, and it's very bad practice. The better ones (Ten Tec Titan, for example) run a 120V fan between one side of the power transfomer primary and the center tap. It is now illegal for the Green wire to carry load current. On Wed,12/24/2014 11:13 AM, Phil Kane wrote: IIRC the latest code update now requires the separate neutral (white wire) to be run in all 240V circuits. I did that in a 1969 when I finished the basement in a year-old home! You may be confusing a 120/240 outlet that has a four circuit plug (phase, phase, neutral, and Green) and can serve both 120V and 240V loads, with a 240V outlet that has a three circuit plug and serves only 240V loads. There is no neutral in a 240V outlet, and as noted above, it is illegal to connect a 120V load between one phase and the Green wire (Equipment Ground). That 120/240 circuit can feed both 120V and 240V outlets. A neutral IS required to feed those 120V outlets. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to n...@sonic.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] 240V Line
It has been awhile since I have worked with the NEC but things haven't changed that much for single phase. It has never been allowed for the green/yellow lead to carry load current. Green and neutral must be the same size as the current carrier even on a 240 circuit. Green and neutral may not be circuit breakered. A 240 circuit may only be split (down to 120) at a panel or sub panel and then each circuit must have its own circuit breaker. 120 volt circuits must have special plugs and sockets if breakered for at more than 20 Amp. Panels or sub panels may not be placed in closets or closely enclosed areas. (This is to avoid heat buildup.) Some areas are requiring arc detecting or GFI interrupters on upgrades. If you install them (generally a good idea) then place GFI/ARC type circuit breakers at the panel. Do not place at load where RFI is likely to false trip. As warned local requirements may vary but this is sort of baseline stuff. Nobody will fault you if you follow. 73 Fred, AE6QL -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown Sent: Wednesday, December 24, 2014 1:50 PM To: Reflector Elecraft Subject: Re: [Elecraft] 240V Line On Wed,12/24/2014 11:41 AM, Charlie T, K3ICH wrote: A lot of the older amps (Thunderbolt for example) had 120 V fans wired from one hot to ground. I always wondered about that. I think that used to be legal, but it is no longer, and it's very bad practice. The better ones (Ten Tec Titan, for example) run a 120V fan between one side of the power transfomer primary and the center tap. It is now illegal for the Green wire to carry load current. On Wed,12/24/2014 11:13 AM, Phil Kane wrote: IIRC the latest code update now requires the separate neutral (white wire) to be run in all 240V circuits. I did that in a 1969 when I finished the basement in a year-old home! You may be confusing a 120/240 outlet that has a four circuit plug (phase, phase, neutral, and Green) and can serve both 120V and 240V loads, with a 240V outlet that has a three circuit plug and serves only 240V loads. There is no neutral in a 240V outlet, and as noted above, it is illegal to connect a 120V load between one phase and the Green wire (Equipment Ground). That 120/240 circuit can feed both 120V and 240V outlets. A neutral IS required to feed those 120V outlets. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to fptowns...@earthlink.net - No virus found in this message. Checked by AVG - www.avg.com Version: 2015.0.5577 / Virus Database: 4257/8801 - Release Date: 12/24/14 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
