Sometimes it may be even a little more than the pay issue; he may be fearful that you're the better electrician and doesn't want you to get the idea that you'd be able to pass him up.
If he gave credit where credit is due, I'd bet my lunch that it'd be both a monetary increase and an admission that you're beyond his level technically or reputation-wise.
He could become a true leader/manager (the good kind) and tout his skill in hiring terrific people if he weren't competing directly with your skills. But people living with or in fear can become jerks in a hurry and will do whatever it takes to ensure that they stay as high up on the heap as they can.
