calimurray

we are currently remodeling a commercial unit thats been built for at least 20 yrs. The problem is the owners have added about twenty new dedicated circuits the plans said to route all new circuits to the existing RP1 panel which is a 120/208 Y system fed by a 45KVA transformer off a 60 amp feed from the MDP,sounds alright so far right well this panel is 125 amp panel with a 100 amp sub panel fed off this with virtually no space at all the owners of the building knew of this a long time ago and were not willing to rectify this situation.

We have added an electric dryer,oven,mechanical cabinets,microwaves,small appliance circuits,washing machine, two fridges, and a few dedicated circuits. We are getting 50,55 amps off each leg at this time all though nothing in use yet.Also getting strange readings of 201volts off dryer outlet.

I guess the question is how long will this 45kva transformer last when everything is being used we currently have about 100 circuits fed off a 125 amp feed. Which will ovr extend 45kva.

We are submitting a change order for a new 75kva transformer feeding a 200amp panel with a 100 amp sub and relocating the 45kva to another electrical room to feed a new 100 amp panel there for the rest of this building. Although the owners of this building are strapped for cash supposedly. What can we do in the mean time to insure that there wont be an overload right now the 45kva is very hot really hot, to touch.

Im not to confident in this old system and any ideas would be appreciated

brian john

It is all about KVA, VoltsXAmpsX1.732=KVA.

Monitor the existing load.
Fan force air across the coils of the transformer.
Keep items off and away from the transformer.
Make sure the load is balanced.

As for the 201 VAC

Check the primary and secondary voltage at the transformer phase to phase and on the secondary phase to phase and phase to neutral.

If this is a product of low primary voltage or reduced voltage due to loading you can change the taps these are typically 2.5%. But if the load varies greatly this could result in over voltage, though 2.5% over 208 should not pose any problems.

calimurray

we removed the 45kva yetserday and replaced it with the 75kva and new 200 amp feed,

Everything is up to par now. The old 45 kva was toast.