After a week of finger-pointing and speculation as to what caused the Super Bowl XLVII blackout in New Orleans, Entergy, the Superdome’s energy supplier, recently released their assessment of this epic outage. It seems, though, that the blame-game is not yet finished. While Entergy officials are citing the innate defectiveness of the relay device, the device’s manufacturer, S&C Electric, is throwing the blame right back onto Entergy for applying incorrect settings to the device.

In December, amid growing concerns about the reliability of the Superdome’s fairly aged electrical system (built in 1975), officials had a relay installed at the switchgear.

What is the switchgear? The switchgear is the point where electricity, supplied from the utility, is distributed throughout a building. Much like your main panel inside your home, not only is this the point-of-entry for electricity for distribution but also where the overall system safeguards and grounding takes place. Unlike your home which is a 120/240-volt system, with a typical over-current protection of 200 amps, the Superdome’s switchgear was located in a vault fed by “medium voltage” – which is thousands of volts and likely drawing thousands of amps.

Circuit breakers act as over-current and short-circuit protection. They are designed to trip or stop the flow of electricity when trouble is detected. Smaller circuit breakers found in your home or business are called thermal magnetic circuit breakers. Over-current and short-circuit detection is found internally within these individual breakers and trip settings are not adjustable. Larger-scale breakers are directed by devices called relays.

A relay is a device that acts as a switch in order safely and reliably control circuits. For these large-scale medium-voltage breakers, relays act as the brains of the operation. Current transformers (CTs) and potential transformers (PTs) detect current flow and voltage entering the system and are connected to the relay. Settings are preset to detect any irregularities, faults, or overloads for the system and are designed to tell the breaker to trip when such conditions are detected.

So it seems officials with the utility Entergy are blaming a faulty relay designed by a company called S&C Electric. S&C Electric is blaming Entergy for putting in the wrong settings. In my opinion S&C should take the majority of the blamebecause a team of engineers should have been there for the installation and commissioning of the relay. Or…maybe it was Vegas…

A full article on the outage can be found by clicking here.