Using USB for Power and the 1/8" Jack for PT Input

zintrinsic · Post by **zintrinsic** » Mon Oct 27, 2014 1:07 am

Hi,

I Just bought a GEM.

In searching the forum I read that the ability to provide PT and power over the Mini USB port is not ready yet.

Is it possible to use the 1/8" stereo jack for PT, but still use the USB port to provide power? I've been looking at this outlet: which provides USB ports directly on the outlet in addition to the standard 120V plugs. I'm hoping to use one plug for the PT and one usb port for power. Otherwise the transformer for providing power that shipped with the GEM makes it hard to fit the cover on my subpanel. However, I'm not sure if using the USB port for power will cause the GEM to ignore the 1/8" jack and attempt to pull PT from the USB cable. Figured I'd check before buying the outlet.

Also, would you recommend using surge protectors with either the PT transformer, the power transformer (or both)? Or will that impact the ability to monitor power?

Thanks

Post by **Teken** » Mon Oct 27, 2014 8:39 am

Using a UPS on the GEM's power supply is good practice and ensures the system is protected against electrical surges / spikes, no power condition that may damage the device.

The PT should not be placed on a UPS as most units do not offer true sine wave output when on battery power.

You can install an electrical surge outlet to protect the PT transformer. As I did to ensure its protected against the same electrical conditions listed above.

Some good brands are Cooper, Leviton, Panamax.

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Post by **ben** » Mon Oct 27, 2014 9:28 am

You can use the Mini-USB connection to power the GEM. That outlet looks fine.

zintrinsic · Post by **zintrinsic** » Mon Oct 27, 2014 12:03 pm

Excellent, thanks for the help. I haven't had much luck finding a 1 gang outlet that provides USB ports and has surge protection.

I'm thinking of using a standard outlet and the following surge protector which will fit in my subpanel and has USB ports:

Will the EMI/RFI noise filtering affect the PT?

Thanks again.

Post by **Teken** » Mon Oct 27, 2014 12:10 pm

zintrinsic wrote:Excellent, thanks for the help. I haven't had much luck finding a 1 gang outlet that provides USB ports and has surge protection.

I'm thinking of using a standard outlet and the following surge protector which will fit in my subpanel and has USB ports:

Will the EMI/RFI noise filtering affect the PT?

Thanks again.

The filtering will not impact the PT's ability to monitor the line voltage. Another solution in case you did not consider is to install a surge outlet and simply plug in a modular USB square plug like those used for the iPhone.

Either solution works fine and comes down to room / clearance and user preference(s).

scyto · Post by **scyto** » Sun Feb 22, 2015 12:30 am

If I use the USB to power the GEM can the USB power be on the UPS (I would still have the jack based PT lead plugged into a normal outlet)?

Post by **ben** » Fri Feb 27, 2015 12:32 pm

scyto wrote:If I use the USB to power the GEM can the USB power be on the UPS (I would still have the jack based PT lead plugged into a normal outlet)?

I don't see why not, you'll have 0 readings while it's down. If your UPS simulates an accurate 60Hz and a fairly pure sine-wave, you could probably hook the PT up to it too.

scyto · Post by **scyto** » Sun Mar 01, 2015 8:36 pm

Thanks, how can I tell if it accurately simulates 60hz?

Edit
Hmm it is stepped to sine, is that ok? http://www.apc.com/products/resource/in ... _watts=200

scyto · Post by **scyto** » Sun Mar 08, 2015 11:48 pm

These ones coupled with the antek worked perfectly to power GEM and DB. I still have PT plugged in mains directly until I hear back about the post above.

New links:

and

thanks for the tip on the UPS.

Post by **ben** » Mon Mar 09, 2015 10:17 am

Getting an internal error with that link but based on the terminology, I wouldn't suggest hooking up the PT to it as it's not a pure sine wave.