June 17, 2012

Understanding Voltage Specifications for Equiping

Frequently we gets requests to provide a transformer or a UPS for a certain piece of equipment.  For many reasons, manufacturers tend to be very curt with the electrical or UPS requirements on their brochures.  What information they do provide can be cyptic.

One area of frustration is matching the voltage of equipment.  Here are some voltage expressions and what the

Type of Voltage Domain
# of Wires
Comments
120 Residential, Commercial
3
Your standard household power
208 Commercial
3
Created from a 3phase source. Standard "IT" voltage
240 Residential, Commercial
3
Also called Delta, because each wire is 120v, creating 240volt across the system. Large machines and your Oven uses this power.
240 Commercial
3
Also called a High leg. Its a single wire of 240v with a neutral and a ground. Caution when working with it.
120/240 Residential, Commercial
4
Split phase system with a separate neutral and ground. Your house panel has this system.
120/208 Commercial
4
Split phase commercial.
120/208/240 Anywhere
3/4
Not a system, but a designation usually meaning it takes any high voltage system (208v, 240, 120/240, etc)
220 No where
?
The stuff of fairy tales

Notice, there is NO 220volt in this country.  Its a commonly used term to describe the average high voltage power, but it does not exist in nature.