store wiring

First, let me say that because of the time it takes to load pages with a slower internet connection, that these pictures have been reduced in quality, and don't show the excellent workmanship of the actual job.
These 2 pictures are taken in the same room of the main service to 3 medium sized stores. On the Top we see the 400 amp 600 volt 3 phase main switch fed with 750 kcm AL condudtors. It feeds 2 x 200 amp switches and 1 x 100 amp switch (and their Meters). These meters do not require Current transformers (ct's) at 200 amps.
The smaller 100 Amp switch is feeding the 600/347 volt panel to its right. That panel is used to feed any 347 volt lighting, or 600 volt motor loads such as a rooftop HVAC unit, or possibly trash compactor and also has a breaker in it is used to feed the 600/208/120 volt 15 kva floor mounted transformer. From this Transformer, the 120/208 volt panel is fed. (you can see the black teck cable from the tranny to the panel) This panel is then used to feed the general lighting, plugs and anything else that is 120/208 volts in the individual store..

Here are 2 more pictures. Left is inside another one of the stores fed from the same service above. The disconnect shown is fed from the disconnect in the main service room above. (There must be a disconnect in the store so the tennant can turn it off if needed). This is the same thing as described above with the disconnect feeding the 600/347 volt panel, and a breaker feeding the transformer, and the 25 kva transformer feeding the 208/120 volt general purpose panel for lighting and plugs etc...

Here we see a bit of an unusual situation. The main service is 600 amps fed to the top black breaker. In the distribution side, there are 4 breakers: 1x 200 amp, 1x 40 amp, 1 x 30 amp, and ?...1 x 600 amp..?... This is done because the large store may have a demand of 520 amps or something similar. So why not just let it be protected by the main 600 amp breaker? What if the large store wants to add something and needs the power off.. It is there also as a disconnect as well as overcurrent protection for the store. In these cases, it is imperative to co-ordinate the trip currents, so that if a fault occures in the large stores 600 amp feed that the stores 600 amp breaker will trip first before the Main 600 amp breaker so as not to interrupt the power to the other stores. We'll talk More about this later.

In the above picture you will see 2 of the meters - 1 from the 30 amp breaker and 1 from the 40 amp breaker.. These feed "house" panels used for common items to both tennants, such as the main street sign, parking lot lighting, and perimeter lighting. In the Left Picture you see 2 more meters, 1 for each of the 2 stores. the meter on the left is fed out of the large "CT" cabinet which contains current transformers for the 600 amp feed. These "CT's reduce the current ratio so the meter only has to read a small current which relates directly to the larger current flowing in the large stores feeder conductors.The meter with the big 3" conduits is only 200 amp, so it doesnt need "CT's" .

The 2" steel EMT going from the 347 volt panel is used for perimeter and parking lot lighting circuits. It comes from the panel to the box located by the 120/208 volt house panel. This box contains a lighting contactor that is turned on and off with the time clock mounted just under it. There are also 2 other contactors beside the tranny that may be for HVAC shutdown from the fire alarm, or more lighting contactors..

This project was done by Horizon Electric of Kelowna who did a very neat job. All the panels and conduits are straight and neat, and it shows the pride of true craftsmen..
Then the phone guys came in....... Notice how they have enhanced the look with their cables that go almost to the roof and then loop back down to form a heart shape. The phone ground surprised me because there were 2 straps that almost lined up within a couple inches of being square with something. I especially like the S look they added to the cable on the left hand side. I wonder if they ever got told to clean up their rooms as kids?.

This is the other house panel, along with the Fire Alarm panel. On the right notice the suspended transformer, and how neat the conduits are installed even in a place where no-one may ever look. Again, these guys have done a great job and should be proud of it.

O.K. its later so here is a brief point on breaker co-ordination....The dials on breakers are used to adjust the time/current curves of the breaker when applying a comprehensive short circuit coordination study. Engineering calculations for your specific system can tell you exactly where to set these dials so down stream breakers trip first before their feeder breakers do. Things that are taken into consideration are transformer size and impedance. Conductor material, size and length. Breaker sizes and types. Load being served.