Arrangements like the one in Figure 4 enable full compliance with the NEC requirement using a temporary generator, such as a truck-mounted or trailer-mounted unit. This arrangement can benefit organizations with multiple facilities, such as a healthcare provider with multiple hospitals in a metro area. Using a single trailer-mounted generator, scheduled service can be performed sequentially at different facilities. Where site layout requires location flexibility, separate transfer switch and connection equipment can be used. The ASCO video entitled ASCO SERIES 300 Manual Transfer Switch Solutions
reviews the applications and benefits of this and other arrangements.
Connecting Supplemental Load
Not only do facilities need to connect temporary power sources, they sometimes need to connect supplemental temporary load. The most common reason is to ensure that periodic testing of backup power systems is completed with load levels that exceed requirements set forth by industry codes. For example, NFPA 110 - Standard for Emergency and Standby Power Systems
and other standards require that monthly tests be completed at loads of 30 percent or more of genset nameplate rating. Temporarily connecting load banks can be used to supplement building load to ensure compliant test results. As with power sources, quick connect panels can be integrated into transfer switches or be installed as stan-alone units. An integrated solution is shown in Figure 5. For more information on using load banks for compliant backup power testing, review ASCO’s document entitled Testing Hospital Backup Power Sources