Any movement in DC wiring in your area?

[fastline]

This mostly pertains to green energy but I am most interested about the actual wiring, voltages, ampacity, etc. We have some low voltage stuff around here in residential but wondering about higher voltages? Is there anything "common" enough to get somewhat standardized? Any movement in the commercial or industrial areas yet?

 

[fuzzysparky]

This mostly pertains to green energy but I am most interested about the actual wiring, voltages, ampacity, etc. We have some low voltage stuff around here in residential but wondering about higher voltages? Is there anything "common" enough to get somewhat standardized? Any movement in the commercial or industrial areas yet?

Oh, you mean like CAT5/data lines?

Or is that what you were hinting at?

I'd think that Electric Vehicle charging stations might meet the criteria of what you're asking, but I have a very rudimentary understanding of them and will let the EV Charging station installers correct me if needed.

 

[hbiss]

You mean as a replacement for 120/240VAC?

-Hal

 

[fastline]

Yes Hal, replacement for 120/240. There is a lot going on with EVs, solar, etc, all of which are DC, meaning there is growing conflict in the AC vs DC debates. Just curious as our area seems to lag behind in advances and trends.

 

[romex jockey]

PV fields & rooftop PV systems for larger commercial building rooftops have become the norm here. the interesting thing about some larger PV fields is they are spotted in areas where heavy substations existed for manufacturing long outsourced. ~RJ~

 

[junkhound]

For a given wire insulation (e.g THHN, NM-B, etc) 315 Vdc is less stress n insulation than 240Vac 60 Hz.

OCPD a totally different story.

 

[tom baker]

Are you familar with the several recent articles in the NEC that are for DC power?

 

[Hv&Lv]

For a given wire insulation (e.g THHN, NM-B, etc) 315 Vdc is less stress n insulation than 240Vac 60 Hz.

OCPD a totally different story.

That’s because 240 VAC = 339 V p to p

 

[Jraef]

DC doesn’t travel well at working voltages, that’s been the problem since the War of the Currents between Edison and Tesla.

 

[LarryFine]

DC doesn’t travel well at working voltages, that’s been the problem since the War of the Currents between Edison and Tesla.

Well, the same Ohm's Law applies to both. I've always thought the main objection to DC was that you can't use transformers.

Modern electronics have overcome that limitation, and DC is being used in some places for high-voltage transmission lines.

 

[Hv&Lv]

Modern electronics have overcome that limitation, and DC is being used in some places for high-voltage transmission lines.

That’s true regarding the transformation of voltages. It’s much easier.
also true though is the advance of modern electronics. I just think it will be hard to mix it with what we have in place today

 

[fastline]

Uh, they are doing high voltage DC transmission right now in a couple places. I don't think it is being fed to homes though. I agree, not as simple as a transformer and I would like to know how they ensure good isolation from the primary like an AC transformer.

I would think certain things like high voltage switching will be complicated because AC arc will self arrest due to the zero crossing, but DC will just give a constant arc. Like to learn more about it. I guess if its semiconductor driven, maybe they just turn the voltage down....lol

 

[romex jockey]

DC doesn’t travel well at working voltages, that’s been the problem since the War of the Currents between Edison and Tesla.

probably why all the pedestal micro-inverters gained popularity?

~RJ~

 

[ggunn]

Uh, they are doing high voltage DC transmission right now in a couple places.

Links between the East, West, and Texas grids are DC because they are not AC synchronized with one another.

 

[Todd0x1]

Well we are seeing that PoE office lighting starting to proliferate so there's that........

 

[tallgirl]

If residential high-ish DC voltage becomes a common thing, it will likely be somewhere around 400VDC. That's where most EV battery voltages are, and I would expect to see some kind of house-to-grid-to-vehicle thing happening. 400VDC also solves the need to boost lower voltage DC, like with microinverters or smaller string arrays, up to something high enough for conversion to 240VAC. The last microinverter I worked on had a 600VDC bus, but only because we weren't storing a lot of energy, just enough to comfortably make half a cycle.

 

[Besoeker3]

If residential high-ish DC voltage becomes a common thing, it will likely be somewhere around 400VDC. That's where most EV battery voltages are, and I would expect to see some kind of house-to-grid-to-vehicle thing happening. 400VDC also solves the need to boost lower voltage DC, like with microinverters or smaller string arrays, up to something high enough for conversion to 240VAC. The last microinverter I worked on had a 600VDC bus, but only because we weren't storing a lot of energy, just enough to comfortably make half a cycle.

Switching is the problem. We made a lot of variable speed DC drives. The contactors were huge and very expensive.

 

[LarryFine]

The DC I mentioned earlier was for power transmission, not distribution or end-user.

 

[Besoeker3]

The DC I mentioned earlier was for power transmission, not distribution or end-user.

Yes. HVDC transmission.

 

[Hv&Lv]

The HVDC is actually cheaper than HVAC depending on distance.
And as mentioned above, makes for easier interconnection Without worrying about such things as frequency, or angular differences.