Recent content by Chas

Are there any multiple plot freeware or shareware programs available?

I am modifying an existing power distribution box. There is a main fused disconnect (for the box) that sub-feeds two fused disconnects. If the sub-fed fused disconnects are rated at 20A and 25A, what should the main fused disconnect rating be. Also, what should the wire size between the main...

The values in Table 9 of the NEC are based on 60HZ. Where can I find tables that are based on 50HZ?

I am working on wiring diagrams that were done by a French company and they make a reference to Buchholtz Alarm and Tripping. What is this?

The project I am on has a 220VDC system with a floating ground. 1. What is a floating ground and why use it? 2. If I buy a DC panelboard, does it need to have 2-pole breakers to break the "+" and "-" lines? Thanks for your help.

I am working on a project in Egypt that has a UPS system. The input is 380VAC/3 phase/50HZ and the output is 220VAC/1 Phase/50HZ. The output shows to have a neutral. I need to add a panelboard on the output. Would this panelboard be a 2 wire type (hot and neutral)?