Stinger? No Main Panel?Something STINKS!

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gdog

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1977 sq.ft. Tenant improvement 400 amp service My faithful electrician says the contractor who built the shell put a stinger in and we need to add an additional panel to split or tap in order to use all the equipment our restaurant needs. what and why a stinger?

[ July 13, 2004, 08:36 PM: Message edited by: gdog ]
 
Re: Stinger? No Main Panel?Something STINKS!

what and why a stinger?
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The voltage system is usally determined by the POCO. If all they had available at your site was 120/240 3 phase delta then thats what you got.

A 120/240 delta system has 240 volts between phases and 120 volts between 2 phases to neutral. One phase to neutral will have 190 volts to neutral. This is known as the stinger.

we need to add an additional panel to split or tap in order to use all the equipment our restaurant needs
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Well maybe. It kinda depends on the quantity of the various type loads. A 120/240 delta system can support 240V single or three phase loads as well as 120v single phase loads. I would think all of your loads would be in one of those three types.

The question may be how many of each type do you have. If you have 40, 120V single phase loads, then 1/3 of the breakers in your panel will not be usable and you may need an extra panel. However, if you can arrange the breakers so that you use the high leg (stinger) for the 240V single or three phase loads, you can get more out of the existing panel.
 
Re: Stinger? No Main Panel?Something STINKS!

I think the typical high-leg is approx. 208V. (120 x 1.732)
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The nominal "high leg" voltage is approximately 208 volts, but voltage drop often results in less than 200 volts at the panel.

By the way, the high leg 208 volts is actually the vector difference between one full phase (240 v) and half of the center-tapped phase (120 v).

Ed

4Wdelta2.gif


[ July 12, 2004, 08:00 AM: Message edited by: Ed MacLaren ]
 
Re: Stinger? No Main Panel?Something STINKS!

Ed, bphgravity, you are correct.

When I started in this business, I had a senior engineer tell me that my calculated 208V high leg voltage was wrong and that the correct voltage was 190 volts.

After I presented much discussion and draw diagrams such as the one Ed presented. He told me that line to neutral voltage is 110 volts not 120 volts and to get back to work.

At that point I remembered who was signing my check and the old adage about winning the battle and loosing the war. Ever since, I have always just used 190 volts. I guess some lessons are hard to "unlearn".

110 * sqrt(3) = 190.5 volts
120 * sqrt(3) = 208 volts

Guess I was using the 110 volt system. Instead of the 120V system. ha ha? ;)

Hopefully, my advice to gdog was better than my calculations.

I have always found it interesting that we can't even agree on the line to neutral voltage of the receptacles we use every day.
 
Re: Stinger? No Main Panel?Something STINKS!

Another panel is needed for certain as we have lights, equipment,two ac units, make-up air and our hood system not to mention we have discovered that the buildings electric room ,common areas,outside lighting and all fire alarm systems run off of our panel!!!The building consists of four units and there is no house panel although there is a spot for one with room for a meter marked in the electric room?Is this common or is something rotten in Denmark??
 
Re: Stinger? No Main Panel?Something STINKS!

I was taught that you could use the stinger in any 240v single or 3 phase load just not on any 120v loads. Its worked so far. Eric
 
Re: Stinger? No Main Panel?Something STINKS!

It is possible to arrange the phases in panel so either the upper part or the lower part is three phase and the rest is single phase. I don't know if this in compliance with UL or not though. In most cases this lets you make better use of your panel spaces.
 
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