Garage wiring - EMF Concern

[mknox]

A buddy of mine had a defibrillator device (kind of like a pacemaker) implanted and received similar warnings from his doctor. Not supposed to keep a cell phone in his breast pocket, use electric shavers and so forth. Most likely precautionary, but I think I'd err on the side of caution in that sort of circumstance. He has been in my Tesla, and I think the car's acceleration is more likely to give him a heart attack than any EMFs it's putting out!

 

[EarlyAdopter]

These warnings are probably from concerns about inductive heating of the metal in the medical device.

 

[AoneOne]

Remembering my EE/Physics education:

The effectiveness of a conduit as shielding depends on the "skin depth" that depends on the conductivity of the metal used and the thickness of the wall. According to Skin Depth Calculator - Microwave Encyclopedia - Microwaves101.com, the skin depth at 60Hz in Al is about 1 cm. So, if the conduit's wall is 1 mm thick, it lets exp(-0.1) = 90% of the wire's field through.

In other words: don't bother trying to shield the wire. If you're really worried, run the cable further from your bedroom. Doubling the distance reduces the field four-fold, but I don't see the need for such a change.

There are other types of cabling that would have lower emissions, such as co-ax, but they're not normally used for residential power applications and forcing them into that application would probably increase the risk of fire far more than they'd lower any reasonable risk from EMF.

 

[wycolo]

> the skin depth at 60Hz in Al is about 1 cm [AoneOne]

So that means there is essentially NO skin effect at such a low frequency since 1cm would envelop the entire conductor. Skin effect begins in the HF range, ~3mhz and up, where shielding is very effective (a long ways below microwaves).
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[linkster]

Toyota's message is due to lawyers, not science. Cell phones and high power lines have been studied without significant findings. Thus at worst it must be a small effect if any. If like mercury in vaccines you have a worry, move the cable slightly.

Tend to agree. Can't remember specifics of pacemaker interference testing protocols in my previous life, but they were quite extensive. I probably wouldn't wrap myself with an HPWC pigtail (with or without an electrical implantable medical device) at 80A, but I certainly would not have an issue with running a 40A branch circuit through my bedroom floor.

 

[yobigd20]

if you have a lot of electricity running underneath your bedroom you'll likely have enough EMF floating around to attract and help ghosts gather enough energy to make their presence known. you'll likely experience odd sounds at first but over time the entity will take more physical form. if you're not lucky you'll get a poltergeist that will torture you and your wife at night and you'll have your very own paranormal activity with you and your bed getting tossed around and eventually the entity will possess your wife and then she'll float above you staring at you for hours while you sleep and then all of the sudden she'll just scream bloody murder to wake you right before she quickly snaps your neck and then she'll disappear with your tesla. happy charging!