Discuss "240V" panel reads 208 line to line? in the Commercial Electrical Advice area at ElectriciansForums.net

Reaction score
9
This must be such a noob question but I cant seem to find any answer out there:
Background: Installing a 10hp Air Compressor 230V 30A 3Ø. The panel I want to use says 240V and there are giant Printers that that are also 3Ø that get their power from this panel. Im not an expert on transformers but there are two in the electrical room both say 480 primary 120/208 secondary and they each provide power to their own subpanel 1 to 1.
So the simplest question to ask first is if my panel is 240V 3Ø or 208V 3Ø or is this the same thing?
Each leg reads 120 to Neutral
Line to line is only 210 (A - B; B - C; A - C)
This isnt 240V 3Ø right? And theres no way to get 230V 3Ø from this panel?
 
This must be such a noob question but I cant seem to find any answer out there:
Background: Installing a 10hp Air Compressor 230V 30A 3Ø. The panel I want to use says 240V and there are giant Printers that that are also 3Ø that get their power from this panel. Im not an expert on transformers but there are two in the electrical room both say 480 primary 120/208 secondary and they each provide power to their own subpanel 1 to 1.
So the simplest question to ask first is if my panel is 240V 3Ø or 208V 3Ø or is this the same thing?
Each leg reads 120 to Neutral
Line to line is only 210 (A - B; B - C; A - C)
This isnt 240V 3Ø right? And theres no way to get 230V 3Ø from this panel?
This would also mean that the Printers are not running at full capacity like they should since they are rated at 208/240V but recommended 230V right?
 
This is one for one of our USA folks such as @Megawatt as the UK/EU norms are very different to the USA.

Here almost all "low voltage" systems are a nominal 230V line to neutral, which is 400V line-line in 3-phase and almost always from a star/wye secondary transformer configuration. The tolerance is -6% / +10% so the range incorporates the old UK nominal 240V and the old EU nominal 220V specifications. Very occasionally in the UK you will see a 2-phase / spilt-phase system where it is 230-0-230V (odd remote farm, for example) but most places that needed more power than our typical 60-100A 230V single phase domestic also would want 3-phase for machinery. It is very rare for us to see anything designed for nominal 460V single phase (480V in old UK specification).

I believe the USA domestic is normally the 2-phase (split phase) system of 120-0-120V but you have a common mix of 120V appliances for lower power and 240V for higher power.

Your 120V single phase (line to neutral) voltage would become 208V line-line in 3-phase star/wye connection (the sqrt(3) factor) but I think you have all sorts of variations that are unheard of in the UK/EU such as the "high leg delta" transformer that gives an odd asymmetric mix of voltages to support split-single and 3-phase.

The high leg delta can proves 120-0-120 on one side for single phase loads, and then 240 line-line for the 3-phase delta connection. However, that also means you have the 3rd line wire at 208V to neutral.
 
Last edited:
Is this same issue as in this post?

 
This must be such a noob question but I cant seem to find any answer out there:
Background: Installing a 10hp Air Compressor 230V 30A 3Ø. The panel I want to use says 240V and there are giant Printers that that are also 3Ø that get their power from this panel. Im not an expert on transformers but there are two in the electrical room both say 480 primary 120/208 secondary and they each provide power to their own subpanel 1 to 1.
So the simplest question to ask first is if my panel is 240V 3Ø or 208V 3Ø or is this the same thing?
Each leg reads 120 to Neutral
Line to line is only 210 (A - B; B - C; A - C)
This isnt 240V 3Ø right? And theres no way to get 230V 3Ø from this panel?
If you have 3 phase, it’s probably 480/208 and I have wired many machines that required 240 and all I had in that plant was 480/208. I bet if you wire your air compressor with 208vac it will still work which will pull slightly more amperage. If you want to up the voltage then change the taps in the transformer.
 
If you have 3 phase, it’s probably 480/208 and I have wired many machines that required 240 and all I had in that plant was 480/208. I bet if you wire your air compressor with 208vac it will still work which will pull slightly more amperage. If you want to up the voltage then change the taps in the transformer.
yes i have 480v at the main source and the two transformers are 208v and i understand now that 208 3 phase will power the compressor just fine i'm using 40 amp fuses at the disconnect and the breaker is 40A as well . i was just overthinking because the default settings for the compressor is 230v but the technician can mess around inside the control panel and adjust any fuses in there that need adjusting. most of the paperwork shows 208/230 as being mostly the same config. with the 480 being a different configuration. Appreciate the feedback, sir. I honestly do. 😊 Thank you.
 
Is this same issue as in this post?

no this was a 3 dimensional cnc machine the latest post is about an air compressor. the cnc needed the higher voltage in order to be in optimal working condition . compressors are a little more flexible. the cnc issue has been resolved as well thanks to help from marconi and everyone that replied there
 
Have you got the part number / detailed specification for the compressor?
yes and i was just overthinking it from the panel side when i could use 208v for the compressor without any problems. ive recently gone from laborer working for my dad to running the whole show myself since my dad moved to memphis to work a 9-5 and i've been doing this for a long time but it's become all new to me all over again somehow. im afraid to mess anything up especially this expensive equipment.
didnt man to start a confession lol
 

Reply to "240V" panel reads 208 line to line? in the Commercial Electrical Advice area at ElectriciansForums.net

Similar Threads

Hello, this is my first post here. I have a little experience with most types of household wiring through a decade of DIY remodeling, and...
Replies
0
Views
759
When I joined this forum a decade or so back, there was a discussion going on about a welder that was connected with a 3-core cable to L1, L2 and...
Replies
3
Views
2K
220 vs 240 outlet questions I have a question understanding the difference between 220 volt outlets and 240 volt outlets. I saw a video online of...
Replies
16
Views
7K
Hello everyone my name is Tarek, i work as a concert and show lighting operator with over 20 years of experience in this field, so i have gained...
Replies
1
Views
2K
I am the homeowner of a hot tub that's been working for well for 6 years. One day the water began to provide a shocking sensation which would...
Replies
37
Views
6K

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock