ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Vibrator Supplies??
by gfretwell - 10/19/19 08:33 PM
FPE in Germany
by NORCAL - 10/16/19 08:24 AM
Help with aging employee advice.
by Bill Addiss - 10/15/19 10:58 PM
Fuse blower plug?
by gfretwell - 10/13/19 03:23 PM
Power factor and transformer efficiency
by TeslaEdison - 10/13/19 04:05 AM
New in the Gallery:
FPE Breaker panel in germany
What is this for?
Who's Online Now
1 registered members (electure), 12 guests, and 8 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
208/120V multifamily services #47050 01/07/05 03:09 PM
Joined: Jul 2004
Posts: 49
GamecockEE Offline OP
A question for my electrical brothers & sisters out there. What are the issues that are out there when it comes to using 120/208 services in multifamily dwellings. Any problems as far as voltage on the appliances such as dryers water heaters, heat pumps etc. Thanks

Work Gear for Electricians and the Trades
Re: 208/120V multifamily services #47051 01/07/05 04:00 PM
Joined: Apr 2002
Posts: 2,527
Bjarney Offline
240V-rated resistance-heating appliances use/produce ¾ rated kW when operated at 208V.

(208/240)² = 0.75

>HVAC stuff should be labeled 208V or 208/230V. It is a misapplication to connect motorized 230V- or 240V-labeled equipment to a 208V system.

Also, two equal phase-to-neutral loads produce full current in the common {technically not a neutral} conductor of a 3-wire 120/208Y circuit fed from two of three phases — not zero as in 120/240V systems.

[This message has been edited by Bjarney (edited 01-07-2005).]

Re: 208/120V multifamily services #47052 01/07/05 04:04 PM
Joined: Apr 2001
Posts: 518
John Steinke Offline
If this is a single pahse service, no problem (as long as the appliances are rated to handle 208- a 240v rated appliance might have problems)

IF you are talking about a three-phase system, with a 208v "wild" or "stinger" leg, you have a problem.
The three phase panel in this case is not listed for use as a "lighting and appliance' panel, only as a 'power' panel. I just had an experience with someone who didn't appreciate this, and had some receptacles supplying 208v! What you must do is use two of the 120v legs to serve a separate single phase panel, and draw your circuits from there.

Re: 208/120V multifamily services #47053 01/07/05 05:57 PM
Joined: Aug 2001
Posts: 329
Steve Miller Offline
I serviced a Leisure World community in MD and they had that setup. The only prob we ever had was when people replaced their individual water tanks and dryers without contacting anyone in the maintenance dept. They always complained that the new stuff wasn't as good as the old ... which it wasn't 'cause the old (original) was 208 only and the new was 240. All their HVAC stuff was common to the building so the individuals never got involved.

Re: 208/120V multifamily services #47054 01/08/05 08:03 AM
Joined: Jul 2004
Posts: 49
GamecockEE Offline OP
Thanks, for the info. Can you find appliances that are rated for 208 such as Dryers & Stoves? Bjarney, a follow up to your response. Does the NEC 3 phase demand adjustment as applied to washers and dryers that utilize a neutral take care of that issue when sizing the load and then sizing the neutral? If I'm misunderstanding you, give me an example if you will.

Re: 208/120V multifamily services #47055 01/09/05 12:30 PM
Joined: Apr 2002
Posts: 2,527
Bjarney Offline
GamecockEE, possibly someone else here can help you with applicable material in Article 220. On appliance-voltage availability, local suppliers can answer that question.


2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman


Member Spotlight
Belmond Iowa US
Posts: 44
Joined: August 2005
Show All Member Profiles 
Top Posters(30 Days)
sparky 10
Popular Topics(Views)
259,660 Are you busy
195,033 Re: Forum
184,447 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3