30A, 5-wire powered furniture?

[apelk]

I always try to get a cutsheet of office furniture so I know what the power and wiring requirements are during the design phase. A lot of the time, they have no idea, so I default to specifying 8-wire, 4-circuit (3+1) configuration. I figure that's a worst case scenario for cost (although that's more of a gut feeling than something I can back up with stats :ashamed1.

So on this particular project I'm working on, I've been told "It'll be a typical 30A, 5-wire connection" to the cubicles, but no cutsheet or further information was provided. I have issue with this. First of all, if they're installing 20A receptacles in this cubicles how are we using 30A circuits? Perhaps they are referring to the ampacity of a multi-conductor cable they are using, but why use 30A? Second, is the 5 wires just three hots, a neutral, and ground? So a three pole breaker, assuming 3 receptacles in each cubicle and wire however many together I feel is appropriate? Again, I've never seen this configuration, can't find info on the Internets, and the only info I did find was that it's more of a pre-1990 configuration.

Just looking for confirmation and experience since I'm not going to get any more information than this. And I don't want to look like an idiot.

Amy

 

[infinity]

I've never heard of a "typical 30 amp, 5 wire connnection" because you cannot use 20 amp devices on a 30 amp circuit

 

[iwire]

My guess is it was a typo or they want 10 AWG for voltage drop.

 

[JoeStillman]

You need to let the interior designers know that there is no such thing as a "typical" multiwire circuit. Think of how many combinations of hots, neutrals, dedicated circuits, grounds and isolated grounds you can get with 5 wires. I always tell them that "5 wires" isn't enough info. You need to know what each wire does. Some furniture comes with an oversized (30A) neutral.

Don't be surprised if the designer thought that two 15 amp outlets on each circuit makes it 30 amps.

 

[apelk]

Thanks for the insight everyone.