garage power supply

No. Should be armoured cable of a lesser size 3 core. Twin and earth is not for outdoor use unless mechanically protected etc. Cable size to be calculated, with distance, load etc taken into account. Also this is not a DIY job as it’s notifiable to Building control, and you need a certificate. But if you are determined to DIY it, go ahead.....

Twin and earth cabling is suitable for in door installations only there for if the garage was directly attached to the house this may suffice. However if the cable is exposed to the elements i.e corrosion and moisture then it would not. We tend to install steel wire armoured cable to all outside areas to offer mechanical protection and due to its strength in construction is harder to penetrate or damage. We also have to consider uv light from the sun as the can affect the cables performance. Installing a new circuit from a consumer unit is notifiable under building control and we strongly recommended a certified electrician under takes these kind of works. Who will also inspect and test the relevant parts of the new installation.

When an electrical installation is designed a number of calculations are made to determine that your cables an protective devices are adequate. The length of the cable, method of installation (trunking, conduit), environment, route if the cable, total expecting load needs to know before star anything. The voltage drop, needs to be calculated to check your size supply conductor. Expecting new circuits to separate them as spares. The work/garage will be have copper pipes (sink), then a separate earth conductor needs to provided as a rod copper. To avoid an earth fault will be transfered from the garage to your home installation. Finally, if the twin and earth cable is protected against mechanical damage and from environment it is ok. But, if the cable runs below ground an armour cable is the best option. Good luck.