And if not what kind of box do I need.

Installing a new breaker in a box with room is fine DIY, but attempting to install a panel DIY is not. You are playing with death...

An electrician has to install the panel and it has to be inspected. End of story.

I am having a tankless water installed and it requires a dedicated outlet. I had not budgeted replacing breaker box, but I guess I'll have to. Does anyone know if it would be cheaper to supply parts for project or just let electrician do it all. If supplying parts, what kind do I need?

Is that a sub-panel? It looks like a poorly/improperly executed DIY job. Are you sure it has adequate service for your tankless WH?

Bottom line, the electrician will have to correct that mess when he puts in the new circuit and panel. He may get the materials wholesale but may also charge you the same retail price that you would pay.

That's the panel that came with house. Had a couple of additions to house and over the years that's what came of if. Problem solved, electrician came and found a breaker not of any use anymore and he will use that for water heater breaker. I know it all needs fixing and I will start saving for the $3,000. job. Thanks for everyone's help and consideration for responding to my problem. It always boils down to money.

Depends if he's doing a whole house vs. a point of use tankless. I had a tiny point of use heater that ran on 15A I think in my outdoor kitchen.

"Installing a new breaker in a box with room is fine DIY, but attempting to install a panel DIY is not. You are playing with death...

An electrician has to install the panel"

Why? I've performed this death-defying act at least a dozen times and it never occurred to me that I was on the brink. Am I missing something important? Presuming that you've shut the power off and know what you're doing, where is the danger?

(Yes, it does need to be permitted and inspected, but that's never been a problem until my current town that won't allow me to pull my own permit.)

You must have had a disconnect switch to throw to kill power to the panel. Not all homes have that. Most of the time the POCO would prefer the meter to be upgraded as well while an old panel is replaced (because the meter is old also) and a new line from the meter to the panel (because the wire is old also). It is not uncommon for electricians to call the POCO and schedule someone to come out and shut off power to your house while working on the main line.

sameold-

What size tankless water heater are you thinking about? Just so you know, unless the one you are installing is a really tiny, point of use water heater, you are likely going to need more than a single breaker. A small tankless will typically require a double pole breaker, and ones large enough to handle whole apartment or whole house needs can require 2, 3 or even 4 double pole, 240 amp breakers, with beefy cable, and a breaker box that is rated for, perhaps, 60 to over 100 amps. Here is a link to a line of tankless water heaters showing the electrical requirements as they increase in size:

Ecosmart tankless