Just a question

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dcspector

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Location
Burke, Virginia
I have a situation in a hi rise condo building. MHP series Magic-Pak self contained heat pump units are installed. These units are electric strip 5kw to 7kw. the name plate ratings show min.ckt. ampacity at 38 amps. The EC ran 8wire with a 40 amp 2p ocpd on....no problem. The name plate rating only shows max. fuse/ brkr at 20 amps. I am confused. At 5000w at 208v is 24 amps.....Note..the only thing mentioned on the nameplate for max. ocpd is 20 amps.
 
dcspector, pet peeve in this area, and generator for a lot of red tags.
The HVAC guys seem to have broken fingers when it comes to marking the appropriate "box" on the lablel or attaching the correct label when installing heat strips in these units.
On every unit I've seen there is mention in the posted manufactures instructions to mark or post the approproate data corresponding to the heat installed.
On most units in this area, the chart is like the one noted in quoaueelectric's
reference and simply needs to be "marked".
If they have not done so, they are in violation of one or more: 110.13, 424.92(D), and/or 440.4(B).
The minimum circuit ampacity (ie: wire size) and max overcurent protection must comply with the data on the chart.
From quoquelectric's info, it woud appear the wiring might not be adequate for the 7.5 kw units, but that is why we us the nameplate..to confirm such things.
 
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