# High Voltage (or High Tension) Lines **URL:** \ **Category:** Factual Questions\ **Created:** [November 2, 2002, 2:23am UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943 "2002-11-02T02:23:38Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [November 3, 2002, 1:53pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/21 "2002-11-03T13:53:06Z")
Everything **David Simmons** said is 100% correct. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [November 3, 2002, 1:59pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/22 "2002-11-03T13:59:56Z")
I forgto to note- the grounded B service is NOT used in residential wiring. Commercial or industrial only. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [November 3, 2002, 2:03pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/23 "2002-11-03T14:03:06Z")
I forgot to note- the grounded B service is NOT used in residential wiring. Commercial or industrial only. Thankyou, Crafterman, for your delightfull responses. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [November 3, 2002, 3:13pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/24 "2002-11-03T15:13:14Z")
> [@](#): > > \*Originally posted by whuckfistle \* > \*\*I`ll back Joey up on this one. You can have a 240 OR 480 volt grounded B service. Sometimes called “corner grounded delta”. > \*\* Ummm, the “delta” system you describe is called that because the vector diagram of the phase voltages looks like a Greek delta and the phase voltages are 120[sup]o[/sup] apart. The system **Joey** described had two voltages 180[sup]o[/sup] apart with the center grounded. Quote: _“Unless you’re in Wisconsin (in the WEPCO service area)…We have a grouded second phase. If you pop open the cover on a 3 phase breaker box, the center phase goes directly to ground, and phase one and phase 3 are 180 degrees apart.”_ In the delta three phase system, if the voltage on each each phase is 120 v., for example, the voltage between the two “hot” lines would be 120\*sqrt(3) = 208 v. and not 240. Not at all the same thing. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [November 3, 2002, 3:57pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/25 "2002-11-03T15:57:43Z")
> [@](#): > > _Originally posted by David Simmons \* > \*\* > for example, the voltage between the two “hot” lines would be 120_sqrt(3) = 208 v. and not 240. > > \*\* Actually the voltage between the two “hot” 120 v. wires in the delta configuration would be 120 v. Is there any graceful way that I can pretend my 208 v. figure cited above doesn’t exist? That I never wrote it? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [November 3, 2002, 4:09pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/26 "2002-11-03T16:09:25Z")
Maybe I should mention that this is at a commercial bussiness. Also I just checked out everything to make sure that I remembered correctly. The box says 3 Phase 240 Volts. I popped the lid and it has two wires running through the switch (and the time delay fuses) and the third wire goes directly to ground. ---
**Author:** ![ScoobyTX](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@ScoobyTX](https://boards.straightdope.com/u/ScoobyTX)\ **Post date:** [November 3, 2002, 5:07pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/27 "2002-11-03T17:07:48Z")
My parents’ house in Houston has 208V 3 phase service, so it isn’t completely unknown for 3ph to be used for residential. The only appliance that is wired for 3ph is the A/C unit. I haven’t seen how other things are wired, but I know that the incoming service is 3 insulated hot wires and one bare neutrals. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [November 3, 2002, 5:08pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/28 "2002-11-03T17:08:13Z")
How do we know the voltages are 180 degrees apart as JOEY stated? Simmons, are you disputing my knowlegde of the existence of 240 or 480 grounded systems? Maybe Joey is describing and open delta system. In any case the physical configuration of the windings is DELTA, or WYE, not just the phase vector diagrams. Take apart a XFMR, and trace the windings to thier sources and you will actually see DELTA or WYE configuration. In a common XFMR the core is grounded. In a grounded B system the tap between A and B is grounded. In a High leg system the B winding is grounded in the center. 120 - 208 is an example of a WYE output 277 - 480 is an example of a WYE output ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [November 3, 2002, 5:13pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/29 "2002-11-03T17:13:08Z")
In a High leg system the A-C winding is tapped in the center. Beg pardon ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [November 3, 2002, 5:47pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/30 "2002-11-03T17:47:26Z")
> [@](#): > > \*Originally posted by whuckfistle \* > \*\*How do we know the voltages are 180 degrees apart as JOEY stated? > \*\* We can only answer the question as it is stated in the OP. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 3, 2002, 6:12pm UTC](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943/31 "2002-11-03T18:12:10Z")
Quoth **StPaul** : > [@](#): > > On the main conductors of a transmission line I occasionally see assorted items such as a large ball bolted over each line or what looks like lead weights connected to the line near the tower connections. Are the balls bright orange? Those are put there in regions where there might be low-flying aircraft, to make the lines more visible. [Previous page](https://boards.straightdope.com/t/high-voltage-or-high-tension-lines/134943.md?page=1)