ECN Forum Forums General Topics of the Trade General Discussion Area Sub-panel off the "back of the meter"

I'd strongly suspect in practice much smaller services would happily supply such a water heater without tripping the main though. In Germany and Austria load calcs are only required for new supplies, nothing keeps you from adding loads to an existing supply even exceeding its rating. Example: one 24 kW tankless water heaters, another 21 kW and a full-sized electric cooker (probably somewhere between 7 and 8 kW) - connected to a 25 A 230/400 V 3-ph supply! Never a blown main fuse! That rare case came up in a discussion on mains supply sizes and how much power modern households really need.

Interesting. That is a somewhat common installation here, using a feed thru Meter base with dual load lugs. It was more popular before the all in ones took over though, now we just use a 400 all in one with a second 200 amp sub feed breaker. I have had a few service replacement situations where that wouldn't work and we went with the dual feed meter base and fed into two main breaker panels.