Forget the electric performances onstage, or the power lighting up the famous spire at night - electrical charge is vital for Arts Centre Melbourne's very foundations.
It's one of the biggest performing arts centres in Australia and the Theatres building, which houses the State Theatre as well as the Fairfax and Playhouse, extends six stories underground on the banks of the Yarra River.
Prime real estate to be sure. But the steel piles anchoring the building to the bedrock below sit in a soupy, corrosive soil known as Coode Island silt.
A system of electrically charged devices known as anodes guard these underground steel rods against decay and, after 40 years, the building's specially designed protection system is in need of replacement.
"It's really, really important that the building is looked after ... It's a tricky piece, but it has to be done," centre CEO Karen Quinlan told AAP.
Pioneering architect Sir Roy Grounds envisioned the building - and its landmark spire - while the red-gold interiors are by Oscar-winning designer John Truscott.
While the State Theatre renovation has been well-publicised (with the Australian Ballet and Opera Australia shifting to commercial theatres), it's the necessary work on the building's foundations that is actually driving the Arts Centre revitalisation project.
The works also include a new rehearsal space, more accessible stage door, bigger loading dock, better seating, lighting and sound, and a two-level restaurant.
The renovation is part of a larger $1.7 billion project to transform the city's creative precinct, including building a new art gallery to be named Fox: NGV Contemporary.
The upgrade is going according to schedule, promises Quinlan, who wants to remind theatregoers that while the State Theatre is closed, the Playhouse and Fairfax are still staging performances.
With hoarding wrapping much of the building, the end of October marks the 40th anniversary of the opening of the Theatres Building and its iconic spire.
"It's an important milestone that we want to celebrate, and we want to see the Arts Centre keep thriving for the next 40 years," said Quinlan.
The occasion is being marked with booked-out architecture and design tours, and the release of a three-part documentary series Building An Icon.
The Australian Performing Arts Collection is showcasing set models from productions staged in the building over the decades, and there is also the release of a furniture collection by Australian company K5 Furniture that pays homage to Sir Roy Grounds' minimalist style.
The first shows programmed in 1984 were Melbourne Theatre Company's Medea in the Playhouse, and A Stretch of the Imagination, presented by the Playbox Theatre Company (later Malthouse) in the Fairfax Studio, and The Australian Ballet's Sleeping Beauty in the State Theatre.
