Laws ensuring the compliance of your electrical work change constantly in order to make sure all electrical work gets completed with the most recent safety measures in mind.
For this reason, electrical work often does not comply with the latest safety standards. With the cost of electrical work many owners and contractors alike choose to take shortcuts to save some costs. These shortcuts might work fine at first but can create expensive repairs much later on.
When working with an existing structure it is also a good idea to first determine what fittings will be compatible with your electrical work. Buying the wrong fittings is an extremely costly affair.
The best way to avoid or deal with electrical disputes is to go with your contractor/electrician when all electrical fittings must be purchased. This will ensure that there is limited room for misunderstandings and miscommunication.