comparing between 480/277V system and 208/120V system

Status
Not open for further replies.
H

hanh

New member
What size of the building or size of load should we choose the 480/277V system or 208/120V system?
 
In some cases, the serving utility will make that determination. If both are available, it will usually be based on the load requirements of the larger systems such as HVAC, Cooking Equipment, Ect...
 
Fire Alarm said:
It's odd that this post was made in the low voltage section.
Click to expand...
I can't speak for the OP, but to some people the difference between "low voltage" and "high voltage" is whether it is above or below 600V. For others (myself included), the line is at 120V. So when you use either term, it is wise to make sure your listener draws the line at the same point.
 
I've always believed that Medium Voltage was below 600v and High Voltage above. But when you mention "medium voltage" to most people they don't know what you're talking about...
 
Fire Alarm said:
I've always believed that Medium Voltage was below 600v and High Voltage above. But when you mention "medium voltage" to most people they don't know what you're talking about...
Click to expand...

I don't think there is a right answer and it is worth noting the NEC does not use the term low voltage. :smile:

Here is a link to MEDIUM VOLTAGE CABLES (5kV to 69kV) 69kV is high to me but I guess it's all relative.
 
hanh said:
What size of the building or size of load should we choose the 480/277V system or 208/120V system?
Click to expand...

Not to resurrect a discussion we've already had in another thread, but I invariably prefer higher voltages where possible. You will have lower currents as a result.
 
drbond24 said:
Not to resurrect a discussion we've already had in another thread, but I invariably prefer higher voltages where possible. You will have lower currents as a result.
Click to expand...


But there are times when the higher voltage system is unnecessary from a cost perspective. The determining factor should be the size and type of loads involved with a specific building.
 
for some reason around here, the utility charges far more for a 480V system as opposed to 208. Some plants, even some substantially sized ones have 208 service with transformer banks to go to 480 for the equipment.
 
There are 2 different reference where we find voltage levels defined.

NEC
LV up to 600V
HV>600V

IEEE
LV<600V
MV 601-69,000V
HV 69,001-230,000
EHV 230,001-800,000
UHV >800,000

But this being the LV forum I would guess nost in here would think differently. I work on mostly MV (15kV and 30kV systems) and some LV (480) so I think about 480V diffently than one who works on 48V systems.
 
Status
Not open for further replies.
Top