Directional wires/cables

@jea48 

You seem to accept that

Light is the fastest-moving stuff in our universe. It travels at 186,000 miles per second (300,000 km/sec)

I'd add "in a vacuum" just for completeness.

You would, I hope, agree that low frequency electromagnetic waves are radio waves and travel at the speed of light.

So would you dispute that the wavelength of 60-Hz radio waves in a vacuum is 186,000 / 60 or about 3,100 miles?  That's about the radius of our planet.

Do you really think the conductors in a circuit board radiate any detectable amount of 60-Hz radio waves?

You might care to read up on the difficulty of communicating with submerged submarines using extremely low frequency radio - see Communication with submarines - Wikipedia

@richardbrand Said:

@jea48

Did you do your practical hospital wiring based on the "false" teachings from your apprenticeship, or based on what you learned here? Be honest.

I did electrical wiring after 2010 the same way as I did before 2010. Why would you think I would do it any different?

Knowing how energy actually flows from the source >>> to the Load doesn’t change anything as for installing electrical wiring.

To keep it as simple as I can for you... Example: A customer has a new piece of equipment he wants connected to electrical power. He may have a spec sheet that specifies what the manufacturer requires for the minimum electrical wiring requirements. Usually it just says it must be wired to meet NEC code. (Not Always)

If nothing is given the name/data plate on the equipment is used. The data plate will show the Phase, voltage, and the FLA (Full Load Amps).

Per NEC, (National Electrical Code), the branch circuit wiring is sized using the FLA times 125%. If the FLA is 27A, 1.25 X 27A = 33.75A. Table 310-16, (and notes), wire size? #8awg copper. That’s It.... Phase, Voltage, and Full load current. (Note: Motor loads use different wire sizing calculations)

Nothing said about current "flowing" back an forth in a circuit. Nothing said about energy flowing in one direction either... Phase, Voltage, and Full load current... (Note, there are, will be, maybe, other things the electrician must take into account, for the wiring method he uses. I kept it simple, for you.

As for this"

@jea48

You seem to accept that

Light is the fastest-moving stuff in our universe. It travels at 186,000 miles per second (300,000 km/sec)

I’d add "in a vacuum" just for completeness.

LOL, that was a quote... I really don’t think the author needed to say, in a vacuum... Most people know outer space is a vacuum.

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@jea48

Thank you for your honesty, You do your wiring the same before and after you ’learnt’ how electricity really works on this forum.

I really don’t think the author needed to say, in a vacuum...

No, but as a physicist I just had to add that nuance before I got accused of getting it wrong! Light slows down in water, glass or plastic by a ratio corresponding to the refractive index of the medium.

In fibre-optic cables, light normally arrives faster if it travels straight down the middle, than it does when bouncing at an angle off the inner surface. This is simply because it has further to travel. So at the end of the transmission, the light is smeared out in time depending on the path it took, which is not good for digital signals

Clever manufacturers use glass with a higher refractive index at the centre, getting lower towards the edges. This is done by changing the composition of glass vapour during vacuum deposition when building up a glass slug. The slug is subsequently drawn into a very fine fibre. The higher refractive index at the centre is designed to slow straight-through photons so the signal arrives all at once, more or less. Obviously this is more important for undersea cables than for component connections, but hey .... if marketed properly some will buy in.

Did you know that space has negative energy? Create more space, and you create more vacuum into which things can "fall". Or that quantum space is not really empty - particles and anti-particles appear and annihilate randomly. That is a credible way to create a universe from almost nothing

....and checked the equipment ground contact of the outlet for a minimum of 4 ounces of contact pull out holding contact pressure. They had a device they plugged into the outlet that had a mechanical pointer that indicated the pulling out resistance in ounces. I can’t remember how often they tested the outlets. ... Next words out of the guys mouth we started testing the outlets on one of the floors and outlets are failing the test.

@jea48 It seems really odd to me that nobody has invented a simple locking mechanism for hospital outlets, or simply use some sort of L14 30R plug like they have on generators to ensure it remains where it should. It is not about contact pressure for "better signal", it is about the likelihood of a plug to become dislodged.  How much money would hospitals save by doing this, instead of the frequent inspections which must add up to some serious coin. 

@mclinnguy Said: 02-27-2025 at 07:39am

....and checked the equipment ground contact of the outlet for a minimum of 4 ounces of contact pull out holding contact pressure. They had a device they plugged into the outlet that had a mechanical pointer that indicated the pulling out resistance in ounces. I can’t remember how often they tested the outlets. ... Next words out of the guys mouth we started testing the outlets on one of the floors and outlets are failing the test.

@jea48 It seems really odd to me that nobody has invented a simple locking mechanism for hospital outlets, or simply use some sort of L14 30R plug like they have on generators to ensure it remains where it should. It is not about contact pressure for "better signal", it is about the likelihood of a plug to become dislodged. How much money would hospitals save by doing this, instead of the frequent inspections which must add up to some serious coin.

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It is not about contact pressure for "better signal", it is about the likelihood of a plug to become dislodged.

IT is absolutely about contact pressure. Especially the contact pressure of the female safety equipment ground contact to the plug equipment ground pin. A good low impedance connection is a must...

Hospital Grade Standards. What is Hospital Grade?

The worst physical abuser of a hospital grade receptacle, that a patient’s bed is plugged into, is the house keeper that scrubs the floor in the room. ??? I actually seen it first hand. The house keeper unlocks the brakes on the bed and gives it hard shove to one side so the floor under the bed can be cleaned. The cord on the bed is only so long. The extreme side pressure on the plug rips it right out of the receptacle. That abuse of the receptacle contacts, especially the equipment ground contact can go well beyond the designed contact holding memory retention.

Hubbell and Leviton hospital grade receptacles can take repeated physical abuse for years. The Pass & Seymour 20A, 8300 hospital grade duplex receptacle outlets made it about one year. There is a very chance they didn’t last that long...

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