Splicing Surge Guard into main power line

[David and Jo-Anna]

I have several questions for the knowledgeable people on this forum about a project I'm thinking of doing. I have bought the 50 amp portable Surge Guard. Rather than hooking it up to the power pole, and having to worry about locking it up, I am thinking of installing it in the basement area by splicing it into the main power line where the power line comes under the staircase to the bedroom just before the main power line goes up to the circuit breaker box. I have purchased a six foot, 50 amp cord designed to be a replacement for an electric range's power cord. I am thinking of cutting the cord in half and splicing these two sections to the two ends of the severed main power line under the steps so that I can bring the connections out into the basement area--that way I can check the lights on the Surge Guard in operation as well as having it accessible if I later want to plug an Autoformer in before or after the Surge Guard.

I have several questions about the feasibility of this project. First, is there likely to be any problem using this 50 amp replacement cord as the means of splicing into the main power line. The cord has a 50 amp male plug at one end and four wires terminating in eyelets at the other end. I have also purchased a 50 amp female box. I plan to cut the six foot cord in half, splice the half with the male end onto one section of the main power line, and use the other half of the six foot cord to connect the other side of the spliced main power line to the female 50 amp box I bought. I will then plug the Surge Guard into the respective male and female ends of this hookup.

My plan is to connect the spliced ends with large (6 gauge) wire nuts, which I will put inside a metal junction box under the steps. Anyone see a problem using wire nuts for these splice connections? Another concern I have is that, upon closer inspection, I see that the 50 amp cord says it consists of two six gauge and two eight gauge wires. Does this represent any problem?

Sorry for the long winded explanation--hope it makes sense. And thanks in advance for your help.