Okay, let's break down the 2020 NEC requirements regarding disconnects and exposed lug protection for a 6-circuit MLO (Main Lug Only) 3R enclosure, specifically in the context of a temporary power pole setup.

Key Sections of the NEC to Consider



230.71(B) - Number of Service Disconnects

This section limits the number of service disconnects to six for each service. This is important because a temporary power pole might be considered a service (or a separate feeder derived from a service).

408.3(A) - General

Panelboards must be protected against physical damage and be installed in a suitable enclosure.

408.3(E) - Working Space

Adequate working space is needed around electrical equipment.

408.6 - Minimum Rating

Deals with the minimum ampere rating of the panelboard.

408.36 - Overcurrent Protection

Specifically addresses the requirements for overcurrent protection for panelboards.

408.37 - Panelboards in Damp or Wet Locations

Addresses the specific requirements for enclosures in these locations, further reinforcing the need for a 3R enclosure.

Article 590 - Temporary Installations

This article provides specific requirements for temporary power, and it references other parts of the NEC. Important sections within Article 590 include:

590.4(J) - Disconnecting Means

Mandates a disconnecting means shall be provided to disconnect all ungrounded conductors for a temporary service.

590.6(A) - General

All equipment must be approved.

590.6(B) - Protection from Accidental Contact

Wiring must be protected from damage and accidental contact.

Analysis and Answer

Here's how to apply the code requirements to your situation:1.

Disconnecting Means is Required

Because you're creating a temporary service (or feeder) at your temporary power pole,

a disconnecting means is required per 590.4(J) of the 2020 NEC. This disconnect must be able to de-energize all ungrounded conductors supplying the MLO panelboard.2. Six Disconnect Rule

230.71(B) permits up to six service disconnecting means for each service. If your temporary pole is fed by a single service (or feeder), then the disconnect on the pole counts as one of the six allowed. If you have multiple temporary poles each fed from the same service, each pole needs its own disconnect.3.

MLO Panelboard Limitations

An MLO panelboard does not have a main breaker. Therefore, the overcurrent protection for the panelboard's circuits is provided by the upstream breaker. If the panelboard has no main overcurrent protection (MLO), then the overcurrent protection must be provided on the line side, at the source of the feeder.4.

Lug Protection



Yes, exposed lug protection is required. Article 408 generally dictates safety measures for panelboards, and this would include barriers or covers to prevent accidental contact with energized parts, which includes the main lugs. You're already using a 3R enclosure, which helps, but internal barriers might still be needed depending on the specific panelboard design and listing. Also, 590.6(B) requires protection from accidental contact.5. 3R Enclosure

Since you're using a 3R enclosure, you're addressing the requirement for protection from the weather (rainproof/raintight). This is a good start and might be required by the AHJ depending on the location of the temporary poles.

Therefore, in summary



Yes, a disconnecting means is required for your 6-circuit MLO 3R enclosure on a temporary power pole. This disconnect must be readily accessible and capable of disconnecting all ungrounded conductors. Yes, exposed lug protection is required. Make sure the panelboard has barriers or covers to prevent accidental contact with the energized lugs. Ensure that overcurrent protection is provided on the line side of the MLO panelboard. The 3R enclosure is appropriate for damp or wet locations and outdoor use.

Best Practices and Important Considerations



AHJ Approval

Always consult with your local Authority Having Jurisdiction (AHJ) for specific requirements in your area. They have the final say on what is acceptable.

Listed Equipment

Use only UL-listed or otherwise approved equipment for your temporary power installation.

Proper Grounding and Bonding

Ensure proper grounding and bonding of the enclosure and all equipment.

GFCI Protection

Consider GFCI protection for all receptacles and circuits, especially in damp or wet locations, as required by Article 590.*

Inspect Regularly: Temporary installations should be inspected regularly to ensure they are in good condition and safe.By following these guidelines and consulting with your local AHJ, you can ensure a safe and code-compliant temporary power installation. Flag for review