Mike Dolt Enterprises
Mike Dolt Enterprises
User: joshgarcia, Location: MA
Asked on: Friday, April 17, 2009 at 3:38 pm EDT
Answered on: Sunday, May 12, 2024 at 4:59 pm EDT
Question: The power plant I work at has been in operation for around 50 yrs. We have two battery vaults that provide 250 vdc to high voltage MCC's for controls. The old vault has the charger/rectifier and disconnect located in the vault along with the batteries while the newer vault, which appears to be around 5 yrs. old, has the charger/rectifier and disconnect located outside the vault and has HVAC ventilation while the old vault is so so on ventilation. I am unable to locate in the NEC where I should relocate the charger/rectifier and disconnect outside the vault to match the newer vault. Both vaults contain the same batteries and I believe they are in the process of adding exhaust fans to the old vault. Any information on this issue is appreciated.
National Electrical Code (NEC) Requirements
Article 480: Storage Batteries
480.12(A): Batteries shall be installed in dedicated battery vaults or rooms. 480.12(B): Battery vaults or rooms shall be ventilated to prevent the accumulation of flammable gases.
Article 480.2: Lead-Acid Batteries
480.24(A)(4): The battery charger shall be installed outside the battery room or vault. 480.24(A)(5): The battery charger shall be provided with a disconnecting means located at the battery charger.Therefore, the NEC requires that the battery charger and disconnect be installed outside the battery vault or room for lead-acid batteries.
Recommendation
Based on the NEC requirements, it is highly recommended that the charger/rectifier and disconnect for the old battery vault be relocated outside the vault. This will ensure compliance with the NEC and provide a safer environment by reducing the risk of fire or explosion due to accumulated flammable gases.
Additional Considerations
Ventilation
The old vault should be equipped with proper exhaust fans or ventilation systems to prevent the accumulation of flammable gases.
Accessibility
The charger/rectifier and disconnect should be located in an easily accessible location outside the vault for maintenance and repairs.*
Coordination with Electrical Engineer: It is advisable to consult with an electrical engineer to ensure proper sizing, installation, and grounding of the charger/rectifier and disconnect. Flag for review