zemingduan
Senior Member
- Location
- Philadelphia,PA
- Occupation
- Electrical Designer
Hi guys, here is the condition:
In a multi-family dwelling units building, a feeder/service supplies 61 dwelling units. Another feeder/service supplies the house panel load. The 61 dwelling units use the VRF system for cooling and heating. Each unit will only have several air handler units supplied by the unit electrical panel. Each air handler unit is basically just a fan and only has around 200-300VA load usually. One central VRF condenser unit will serve several units. These VRF condenser units will be supplied by the house panel.
My question is:
When you use 220.84 to calculate the electrical load for multifamily dwellings, 220.84(A)(3) requires each dwelling unit is equipped with either electrical space heating or air conditioning or both. However, in the condition above, only air handler units are supplied by the unit electrical panel. Can we still use 220.84 to determine the load and feeder for the 61 dwelling units? If yes, what's the load shall we include in the "larger of air-conditioning load or the fixed electrical space heating load" described in 220.84(C)(5)? Can we just include air handler units load? If no, we can only use Article 220 Part III to calculate the load and feeder for 61 dwelling units, but which will result in a much larger load.
What are your thoughts on this?
In a multi-family dwelling units building, a feeder/service supplies 61 dwelling units. Another feeder/service supplies the house panel load. The 61 dwelling units use the VRF system for cooling and heating. Each unit will only have several air handler units supplied by the unit electrical panel. Each air handler unit is basically just a fan and only has around 200-300VA load usually. One central VRF condenser unit will serve several units. These VRF condenser units will be supplied by the house panel.
My question is:
When you use 220.84 to calculate the electrical load for multifamily dwellings, 220.84(A)(3) requires each dwelling unit is equipped with either electrical space heating or air conditioning or both. However, in the condition above, only air handler units are supplied by the unit electrical panel. Can we still use 220.84 to determine the load and feeder for the 61 dwelling units? If yes, what's the load shall we include in the "larger of air-conditioning load or the fixed electrical space heating load" described in 220.84(C)(5)? Can we just include air handler units load? If no, we can only use Article 220 Part III to calculate the load and feeder for 61 dwelling units, but which will result in a much larger load.
What are your thoughts on this?
