![electrical - Installing of Honeywell Wi-Fi Programmable Thermostat - Home Improvement Stack Exchange electrical - Installing of Honeywell Wi-Fi Programmable Thermostat - Home Improvement Stack Exchange](https://i.stack.imgur.com/OrEg6.jpg)
electrical - Installing of Honeywell Wi-Fi Programmable Thermostat - Home Improvement Stack Exchange
![wiring - Can I just extend this blue wire in furnace for Nest thermostat? - Home Improvement Stack Exchange wiring - Can I just extend this blue wire in furnace for Nest thermostat? - Home Improvement Stack Exchange](https://i.stack.imgur.com/6my9i.jpg)
wiring - Can I just extend this blue wire in furnace for Nest thermostat? - Home Improvement Stack Exchange
![My current thermostat does not a C wire connected to it but the incoming bunch has an extra blue wire that is not connected in both ends. Is it ok if I My current thermostat does not a C wire connected to it but the incoming bunch has an extra blue wire that is not connected in both ends. Is it ok if I](https://preview.redd.it/16kai2jed9471.jpg?width=2992&format=pjpg&auto=webp&s=d53dd000afea9a018d6df491fe4621579aacf738)
My current thermostat does not a C wire connected to it but the incoming bunch has an extra blue wire that is not connected in both ends. Is it ok if I
![hvac - Can I use this unused blue wire as my C wire for my new Nest thermostat? - Home Improvement Stack Exchange hvac - Can I use this unused blue wire as my C wire for my new Nest thermostat? - Home Improvement Stack Exchange](https://i.stack.imgur.com/IpvcC.jpg)