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                                    單項選擇題
                                    
    在通常采用的380/220V三相（）線制電壓中性點（）接地系統(tǒng)中采用保護接零技術。
    
                                
    
                                
                                    
    
	A、3，直接
    
	B、3，不直接
    
	C、4，直接
    
	D、4不直接
    

    
                                
                                
                                
    
                                    
                                
    
                                

                        
    
                    
                
    

                
                    
                    

            
    
            
    
                
            
    
        
    
    
    
    

    

    
    
    
        
    
            
    
                
                
    

                
    
            
    
        
    
    
    

    

    
    
    
        
        
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