3 Phase Junction - Electrical - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical


Thread Tools Display Modes
Old 01-09-2013, 01:58 PM   #1
Join Date: Jan 2013
Posts: 1
Rewards Points: 10

3 phase junction

Good afternoon,

I'm currently need to plug in two 3phase compressors and also have 4 110 outlets. I was wondering if I could use one 3 phase recepticle and plug a breaker box into it and then wire the needed recepticles into that. It's a mobile system so I dont know if I will always have all the recepticles that I need and if I can just plug everything into one that would be extremely helpful.

Thanks for you help.


Ravenix is offline   Reply With Quote
Old 01-09-2013, 04:19 PM   #2
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 7,971
Rewards Points: 1,548

Yes you could make up a portable breaker box (subpanel) with breakers rated within the maximum circuit rating for each air compressor, and with 15 or 20 amp breakers for the 120 volt stuff. If a piece of equipment normally draws 20 amps but is spec'ed for a 30 amp circuit, you may not connect it, or two of them, directly to a 60 amp circuit.

Now you cannot have 120 (110) volt circuits or subcircuits unless the 3 phase supply has a neutral specifically for 120 volt usage. This neutral might be symmetric (120/208 volt wye system) in which case any hot can be used wih the neutral, or may be associated with two of the three hot legs (120/240 volt delta system).

And the system must match the compressors' voltage ratings in terms of 240 versus 208 volts. Some 3 phase equipment will work on either 240 or 208 volts and the instructions or name plate will state that.

You may find it handy to have some adapters (receptacle to fit your portable breaker box, plug of lesser amperes rating) for use at different venues which might not have the same amperage circuit to give you. The box itself, its feed cable (wire gauge), and the plug at its end must all be rated for the maximum amperage circuit you will encounter in your travels.

You may not construct, possess, or use an adapter or Y connector with two male plugs on it. Such might be used to get a single allotment of 60 amps from two receptacles on separate 30 amp circuits, which usage is not allowed.


The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.

Last edited by AllanJ; 01-09-2013 at 04:39 PM.
AllanJ is offline   Reply With Quote
Old 01-09-2013, 04:28 PM   #3
Electrical Contractor
jbfan's Avatar
Join Date: Jun 2004
Location: Newnan GA
Posts: 7,027
Rewards Points: 650

What voltage is the compressors?
480, 240 ,208?
"The problem isn't that Hillary Clinton lies. We all know she lies. The problem is that her supporters don't seem to care"
jbfan is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
hELP! Amperage needed for 220V motors 1488rob Electrical 36 01-28-2014 04:44 PM
Three phase transformer question rongaudier Electrical 8 03-08-2011 07:19 AM
Wiring Single Phase through 3 Phase socket tonyr417 Electrical 10 10-26-2010 09:09 PM
Want to add a single phase Subpanel to three Phase Main meglomachinist Electrical 19 09-10-2009 03:46 PM
120/208/1 phase wiring questions JohnJon Electrical 11 08-31-2008 11:28 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1