{"id":6683,"date":"2021-06-24T16:07:01","date_gmt":"2021-06-24T15:07:01","guid":{"rendered":"https:\/\/pq-as-a-service.com\/?p=6683"},"modified":"2021-06-24T16:07:01","modified_gmt":"2021-06-24T15:07:01","slug":"load-study","status":"publish","type":"post","link":"https:\/\/pq-as-a-service.com\/en\/load-study\/","title":{"rendered":"Load Study with DranXperT"},"content":{"rendered":"
DranXperT Survey Study: officially published by Dranetz<\/a><\/pre>\n
Introduction on this load study<\/h3>\n
The National Fire Protection Association (NFPA) publishes NFPA 70, the National Electric Code (NEC). The NEC is the US reference for the safe installation of electrical systems. Although the NEC is not mandated by the US federal government, most states and\/or municipalities in the US require compliance with NEC requirements.<\/p>\n
NEC article 220 is for branch circuit, feeder, and service calculations and section 220.87 covers the requirements to determine existing loads. Compliance with NEC 220.87 is a requirement to determine available capacity when adding loads. For this purpose a load study with DranXperT was executed.<\/p>\n
NEC 220.87 requirements<\/h3>\n
NEC 220.87 states that it is permissible to use the actual maximum demand when determining existing loads, but there are conditions.<\/p>\n
The first condition is that the maximum demand data is available for 1 year. Practically speaking, unless the facility has existing branch circuit or other monitoring, 1 year of demand data may only be available at the utility service from utility billing.<\/p>\n
There is an exception if maximum demand data is not available for 1 year – the calculated load can be measured at the feeder or service. Such a measurement requires a minimum 30-day load study by a power logger measuring the demand averaged over a 15-minute period. The load study must be taken while the space is occupied and include
\nmeasurements or calculations of the heating and cooling equipment (whichever is larger). Refer to NEC 220.87 for specific details.<\/p>\n
Another condition is that 125% of the maximum demand plus the new load does not overload the circuit. The requirements for overload protection are covered elsewhere in the NEC.<\/p>\n
Configuring the measurement device for the load study<\/h3>\n
For this study a DranXperT<\/a> device has been used. Configuring DranXperT for a NEC 220.87 load survey is simple, and the settings are virtually identical to any other load study. It is important that you do the following to meet the requirements of NEC 220.87:<\/p>\n