Alpha Technologies BPT Series Bypass Transformer - Manual (Page 12)

3.3 Circuit Breaker Rating and Wire Guage
Systems with a Bypass Isolation Transformer Installed:
Install a Bypass Circuit Breaker with the current rating specified in Table 2. Use the wire
gauge, as specified, for all connections to the Bypass Switch, especially if there is 208V or
240V supplied to the load.
CAUTION: For UPS output configurations which supply both 120V and 208 / 240V
loads, care must be taken not to overload either of the output windings of the Bypass
Transformer. The maximum current of each output winding is limited to the current rating
at 208V (i.e., the maximum current rating for L1 or L2 is the VA rating of the transformer
divided by 208). Although CFR models up to 5000 VA are capable of supplying the
full rated power at 120V from L1, systems with a bypass transformer must have the
120V loads split between L1 and L2. For CFR models 7.5K and greater the Bypass
Transformer rating is the same as the UPS output rating. Refer to the CFR Operator’s
Manual for a complete description on Load Sharing.
Without Bypass Isolation Transformer Installed:
Install a Bypass Circuit Breaker with a current rating shown in Table 2. Use the wire size
specified for all connections to the Bypass Switch.
The Alpha BPS Series
Doc# 020-133-B0 Rev. 01 / 07
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