Since they’re still in preorder, and haven’t shipped, your best point of data would be the marketing pictures on Sonos.com, none of us have them yet. 

@lovetractor Thanks for bringing this up.  Of all my concerns, I forgot about that.  I actually bought a compatible cord for the Beam so that I could run in the full length I needed to get to my cabinet where my Panamax power conditioner is at.  It will be nice if the end that goes into the Arc matches.

Here’s an unboxing video of the Arc.  If you pay close attention, they show the power cord, which appears to be the same connector as the Beam.  

https://www.youtube.com/watch?v=fSsQjZ_albo

The Arc power cord is different to all the prior Sonos products. It is INFURIATING for the situation you describe.

I have had a Playbar for 5 years, the wall was opened up to discreetly install power and optical connection. Fortunately I left a pull sting in the wall so when I ordered my Arc I used that to pull thru an HDMI cable in prep for the Arc.

Tonight I mounted up the Arc and… the power cord does not fit. Despite all Sonos gear being based on the IEC C7/C8 standard the original Sonos equipment had a modified version and with this new generation it is modified again. The Gen3 sub uses the same.

I think a standard C7 is more likely to fit the newer equipment, which has a shallower C8-like receptacle than the originals, but the power cable from the original Sonos equipment does not fit the Arc nor Gen3 sub. Infuriating.

I very carefully used the old power cable to pull a pull cord through the wall and then used that to pull the new power cable through. I was lucky and successful.

Clarification - The Arc and the Beam do have the same power cable.

I checked against a Beam I also have and it too has this newer modified C7 cable.

The Playbar, 1, One, 3s, Gen2 Sub etc that I own use a different cable to these newer products.

Arc power cable Need a short one. Anybody know the model number? Thx 

exactly the same, I just left mine in the wall when replacing Beam with Arc

What state do you live in that allows power cords inside the wall? 

Is it the same HDMI cable too? 

What you are doing by running a power cord through your wall is not only against building code but dangerous. 70% of electrical fires are due to faulty wiring or using inappropriate power lines. 

Please take that power cord out of your wall and put a proper receptacle behind your soundbar. 

concealing power cables is done by creating a power outlet on the wall behind the device, for wall mounted TVs, this is accomplished by creating a new power source close to the mount itself and for the sound bar  it should be no difference whether its mounted or not, if you create a power a horizontal power outlet, the beam will conceal it as well. putting power inside wall is a very bad idea for so many reasons. the only cables you can run behind a wall for this purpose are HDMI and Ethernet cables. be careful and stay safe. not sure how god concealing power in the wall would be if you need to mount a bright red Halon fire extinguisher right next to the TV….just sayin!