I was working with a group this week and we were in a discussion about making sure that their Scrum teams do the proper level of capacity planning for each sprint in order to avoid overloading. We took a break and I was looking at a home grown power distribution system in the room where two strings of 3-4 power strips each were connected in parallel to two outlets in the floor. No surprise, seen that before. But it got me thinking of yet another metaphor...
Each of the outlet strips has a circuit breaker on it, and the building has breakers for the circuits running through the building. Below is a excerpt from howstuffworks.com explaining circuit breakers:
The circuit breaker is an absolutely essential device in the modern world, and one of the most important safety mechanisms in your home. Whenever electrical wiring in a building has too much current flowing through it, these simple machines cut the power until somebody can fix the problem. Without circuit breakers (or the alternative, fuses), household electricity would be impractical because of the potential for fires and other mayhem resulting from simple wiring problems and equipment failures.
Harris, Tom. "How Circuit Breakers Work." 09 May 2002. HowStuffWorks.com.
Fires and Mayhem! Yikes! Sounds like a few of the projects I've seen in my career. So I thought it would be a good topic after the break to point out what happens when we run too much current through a wire with a certain capacity (no, I did not light the place up!)...a good chance of fire and mayhem. Circuit breakers establish the parameters that allow power to effectively and efficiently flow through the system. When the limits are hit, the breaker shuts down the whole circuit until action is taken to bring it back within limits.
Establishing the teams capacity and the "focused task time" keep the team safe and allow them to increase their speed with experience and learning. When overloaded they often wind up in fire and mayhem.
What are your team's circuit breakers for the sprint? How do you establish the parameters? What signals your breakers to trip? Who has to take action to reduce the load if they do trip? Do you have surge protection?