Implementing 5V on-board transformer correctly

I am designing a PCB to handle relays, current measurement, and step down 120VAC to 5VDC.

I was planning on using this power supply http://www.cui.com/product/resource/vsk-s10-series.pdf, but I have a few questions about it.

Since it is regulated power, is it safe to connect the Arduino 5V directly to V+ on the supply and GND to -5V, bypassing Vin?

Do I need EMC filtering, or is that overkill? Is it required for FCC? If so, I am having trouble finding a suitable 120V Common Mode Choke (NF on the circuit schematic).

If I use the EMC, I will have a chassis ground. Should I just run that back to the origin of the ground on the pcb to avoid ground loop? Can -5V touch this?

I didn't realize implementing this would raise so many questions. I wish I could just use a wall wart!

Thanks in advance

Why can't you use a wall wart?

It's run off of a 240V circuit in the US, meaning I have 2 120V lines to split, but can only do that inside the panel. I would either have to include a 240V outlet and use a corresponding wall wart, which would be expensive. If I could pull just one leg into a junction and put an outlet on, that would work, but then it wouldn't be up to code given that it's a 240 breaker. The breaker would still work, but it wouldn't pass inspection.

I see. Thanks for the explanation.

Common mode choke, 20mh

Thanks for the link!

It was really hard to search for these. I kept finding 40 or 50 VAC units.

Cheers!

ipad ac apapter AC 100-240 Volts, 50-60 Hz 5v 2.1 A

Apple iPad 10W USB Power Adapter by Apple, Amazon, $13.99 & FREE Shipping

iphone ac apapter AC 100-240 Volts, 50-60 Hz 5v 1.0 A

Apple 5W USB Power Adapter by Apple, Amazon, $14.95 & FREE Shipping

Mean Well Panel Mount AC-DC converter 15W RS-15-5

DC: 5V
Current: 3A
AC: 85-264 V

RS-15-5, Alliedelec, $16.77

The iPad charger is a good idea, but then I still have the issue of not being allowed to wire 240v to an outlet with the 120v configuration. I would have to use a 240v outlet, so would need an adaptor for the plug. Here's a outlet that would work http://www.stayonline.com/detail.aspx?id=4772, and I'm not sure if there is an approved adaptor to go between the two.

The Mean Well unit looks pretty good, and cheap. The transformer alone I wanted to use is $20. This really depends on the enclosure I will use. I wanted to shrink it and make only one electrical connection. I would need to make the junctions inside the panel, since again I would be splitting the 240V circuit. That could work if I find the right panel.

Thanks for the tips!