You could be liable for the loss, injury or damage caused to any other person if there is an incident which arises from your negligence which would include making or doing something that you are not qualified for. It would not arise if the article was misused where you have given clear instructions for use. You should perhaps think about getting a disclaimer signed to cover that eventuality.
The disclaimer would say that you are not responsible for any loss or injury or damage arising from misuse of the article or use outwith the given instructions. You can't contract out of liability for not being an electrician. To be safe with that you should get it signed off by an electrician.