simple electrical question

Hi folks, In our office - we have an electrical outlet (large 3 prong electricians just installed). It is supposed to be 208 Volts...
we were having some problems with our equipment, so I ran a multimeter on it - and when I hook up the hot and neutral to the meter (analog type), I get the correct reading of 210volts +/-.
when I connect to the hot and the GROUND I get 120 volts... is that correct, or does the electrician need to come back out? I thought hot and ground should also produce the 210 volt reading...
Thanks in advance!
- Jay
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you got 208 volts between hot and ground, you'd have really big problems. It should read roughly 208 between the two hot legs, and roughly 120 volts between either hot leg and ground
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There is also the possibility that you need three phase 208 volt. It would help if you post the actual electrical requirements of the equipment you're trying to operate

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

i have been thru this in malls, check the volatge at different times of the day, i found it swung wide, and caused great machine troubles. floating neutrals and a idiot electrician.
i finally gave up and dumped the customer, the hassle just wasnt worth it.
commervcial buildings have wierd wiring troubles
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 7 Mar 2008 13:20:03 -0800 (PST), RedDwarf

Where are you getting large 3 prong electricians?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

OK. This from a 3 prong electrician. Presently in Middle East where all domestic electricity tend to be 3 phase and 230 volts phase to neutral! Forgetting all that, but boy those plug in 230 volt appliances often heat up fast! Would you believe a 2200 watt 2 litre kettle!
We are without all the info to go on from the OP and presuming this is in North America or somewhere similar?
But as mentioned what is it for? What is the equipment to be plugged in? Does it require a 3 phase supply? The 208 volt number sounds suspiciously like the voltage between two phases of 3 phase supply!
Howerver if the electrical supply in the environmernt mentioned requires to be similar to that in a typical North American domestic sitaution. (But not Europe or elsewhere), what you have installed 'may' be OK. . To the OP. Domestically and in many 'light' buildings there are typically a three wire supply. (And a ground wire; ignore the ground wire although it is essential for safety, for a moment).
Between each of the 'outer' wires or legs and a centre point (neutral), which if present but may not be required in this case, is usually a white wire which is at approx. zero volts; there should be about 110 to 125 volts.
One way (although not completely correct) to think of this is to imagine a red wire leg being at plus approx 115 volts and a black wire leg being at minus 115 volts. So between the two there is approx 115 + 115 = 230 volts.
If between the two outer wires there is approximately 210 to 230 volts. This could be very similar to what an electrical home clothes dryer connects.
If you have a 3 wire socket, installed correctly and it is correct for the equipment to be plugged into it requiring 230 volts 'single phase' the third pin should be the safety ground and your measurement of approx 210 to 240 volts between the two live pins may indicate all is OK.
A few other questions! Is this a dedicated circuit, for a special purpose machine? Does it have a separate circuit breaker of the correct rating to match the gauge and type of wiring used (not the machine itself)? Or ist a circuit shared with other outlets/sockets?
Just telling someone to install a 230 or 208 volt outlet without other specifications may not have been sufficient info!
Rather like telling someone they need a new battery without specifying if it is for a boat, a heavy truck, motorcycle, garden tractor or flashlight!
Sorry for the length of this comment but the original post raises questions.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There is _no_ neutral in a 208V circuit. Just two hots and a ground. It's the same arrangement as a pure 240V circuit (no 120V loads) - two hots and a ground.
A 208V circuit is derived from a 3 phase (of the right type) circuit. It's just two of the three hots and a ground.
So, 120V between either current carrying conductor and the ground, and 208 between the two current carrying conductors is EXACTLY what you SHOULD be seeing.
I assume that one of the conductors is white - that's what's fooling you. It's not a neutral. (It should be marked or taped to black or red).
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

As others have assured you, this is normal, just as the same outlet in your home would show 240 and 120, respectively.
It's because North American commercial properties are generally fed with scheme called "three-phase wye" (or "Y"), about which Wikipedia or a bit of Googling can tell you lots.
The two hots were 208V apart, and each was also 208V from ground, well, that just wouldn't add up. (Though if the hots were transformer- isolated from ground, then...well, no, not even then.)
Is there some *reason* you needed to test the outlet after installation? Did your new computers just not work?
Chip C Toronto
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

we had a problem with the UPS (battery backup). it turns out it was the UPS. Thanks for the reply... I understand how it works now.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.