Casella CEL CEL-278 - Manual (Page 18)

Incorrect installation, handling, operation, and disposal of batteries can be
dangerous. Follow the battery manufacturer's recommendations, and if in
doubt, seek the advice of a specialist.
When measurements are required over long periods, the CEL-3732/2 Power
Supply may be used. This has sufficient capacity to drive both a CEL sound
level meter and the Filter Set.
Connection and operation of the CEL-3732/2 Power Supply with the Filter
Set and various sound level meters is described in Chapter 5. In general
when using an external power supply, observe the following warnings.
Warning
A potentially hazardous situation can arise if any external power
supply is connected while the internal batteries are still in place In the
Instruments to be powered.
The instruments will be damaged it operated on the 12V (CEL-262)
setting of the CEL-3732/2 Power Supply.
Page 18 CEL-278/2 Handbook CEL Instruments Ltd